JPH0533691A - Generating controller of alternator - Google Patents

Abstract

PURPOSE:To control an alternator optimally so as not to interrupt power generation unduly and to entail any drop in engine speed. CONSTITUTION:A control unit 10 is provided with a voltage variation calculating means 11, calculating a voltage variation in a short space of time of a battery 3, a control mode setting means 12, setting a control mode according to the voltage variation, and a control signal decision means 13 outputting a control signal conformed to each control mode. When the voltage variation grows larger due to a sudden increase in a current consumer during idling or the like, a duty control signal of the control mode conformed. to that is outputted, forcibly controlling the power generation of an alternator 1, and the restraint of power generation is held down to the minimum, securing the charging, and owing to generating restraint of the alternator 1, any possible drop in idling speed and so on can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an alternator (alternating current generator) for generating power from engine power in a vehicle engine to charge a battery and supply electric power to various electric loads.

[0002]

2. Description of the Related Art Generally, a vehicle engine is equipped with an alternator for generating electric power by engine power. The alternator is connected to a battery through a regulator and an ignition switch, and the ignition switch is turned on.
The battery can be always charged when the engine is normally operated. Here, in recent years, in vehicles, there is a tendency to electrically control and operate not only an engine but also a vehicle body, a brake system and the like, and as the power consumption increases, an alternator having a large power generation capacity has been used. Therefore, when the alternator is generating electricity, the load applied to the engine is relatively large as compared with the time of interruption. Therefore, if the driving torque of the alternator increases due to a sudden large electric load during idling or during low-speed, low-load operation, engine speed may drop and engine stall may occur. Therefore, as a measure to prevent this engine speed drop and engine stall,
In the method of increasing the intake air amount and raising the idling speed during the operation of the electric load switch, the fuel consumption and the like are deteriorated. Therefore, the method of controlling the power generation operation of the alternator is preferable.

Regarding the control of the alternator, for example, there is a prior art disclosed in Japanese Patent Laid-Open No. 58-131342, and when the engine speed falls below a set value, the power generation of the generator is suppressed or stopped. In addition, JP-A-57-35
In the prior art of Japanese Patent No. 137, it is shown that when returning to idling, the power generation action of the alternator is stopped for a predetermined time, and the idling rotation speed can be reduced.

[0004]

By the way, the above-mentioned prior art is merely a means for interrupting the power generation of the alternator when the engine speed is low or when it is returned to idling. Here, the control of the alternator has a direct effect on the charging characteristics of the battery.Therefore, unless it is properly controlled, power generation is interrupted excessively at high engine speeds, and the effect of preventing engine speed drop is reduced. There is a problem such as not being able to exert the timely.

The present invention has been made in view of this point, and it is an object of the present invention to optimally control an alternator so as not to excessively interrupt power generation or reduce the engine speed.

[0006]

In order to achieve the above object, the present invention is a control system for generating an alternator by a duty control signal from a control unit, wherein the control unit calculates a voltage change amount of a battery within a minute time. Voltage change calculation means, control mode setting means for setting a control mode according to the voltage change amount, and control signal determination means for outputting a duty control signal according to each control mode.

[0007]

According to the above structure, the alternator is generating electricity as needed when the engine is operating. In this state, the voltage change amount of the battery is calculated in the control unit, and the voltage change amount is increased due to the sudden increase of the electric load during idling. When it becomes larger, the duty control signal of the corresponding control mode is output and the power generation of the alternator is forcibly suppressed, so that the suppression of power generation is minimized to secure the charge and the idling is suppressed by the suppression of power generation. It is possible to prevent the rotation speed from dropping.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. Referring to FIG. 1, the control system of the present invention will be described. Reference numeral 1 is an alternator.
2 stator coil and field coil are regulators
, The stator coil of the alternator 1 is connected to the battery 3, and the regulator 2 is connected to the battery 3 via the ignition switch 4. The alternator 1 is driven by being connected to a crankshaft of the engine via a belt and generates an output according to the number of rotations. Regulator 2
Changes the field current of the field coil with respect to the output voltage of the alternator 1 and adjusts it to a specified voltage. At this time, if the voltage of the battery 3 is reduced, the battery 3 is charged to substantially generate electricity. The switch means 5 is current-controlled by a duty control signal from the control unit to forcibly suppress the power generation operation of the alternator 1 (see FIG. 6).

Explaining the control system of the control unit 10, it has a voltmeter 6 for detecting the voltage V of the battery 3. The control unit 10 has a voltage change amount calculation unit 11 to which the voltage V of the voltmeter 6 is input, and calculates the voltage change amount ΔV from a voltage change within a minute time. This voltage change amount ΔV is the control mode setting unit. Enter in 12. The control mode setting unit 12 compares the voltage change amount ΔV with a set value to determine a change state, determines a control mode in which, for example, three stages of suppression time are different according to the voltage change amount ΔV, and determines the control signal determination unit. 1
3 outputs a duty control signal corresponding to the control mode to the switch means 5.

Further, the engine idling control system is
An idle control valve 22 is provided in a bypass passage 21 that bypasses and communicates with the throttle valve 20 of the intake system. And
The idle control unit 23 is configured to change the degree of opening of the idle control valve 22 by determining the engine state, electric load, etc. during idling. Therefore, the control signal is also input to the idle control unit 23, and when the idle control valve 22 is opened due to an increase in the electric load, it does not operate while the control signal is input.

Next, the operation of this embodiment will be described with reference to the flow charts of FIGS. 2 to 5 and the time chart of FIG. First, the main routine of FIG. 2 is executed during engine operation, the battery voltage is read in step S1, and the voltage change amount ΔV is calculated in step S2. Then, this voltage change amount ΔV is compared with the largest setting value ΔV1 in step S3, and the intermediate setting value Δ is calculated in step S4.
It is compared with V2, and is compared with a small set value ΔV3 in step S5. Therefore, when the electric load is small and the voltage change amount ΔV is small as indicated by the solid line in FIG. 7 during low-rotation, light-load operation such as idling, the process shifts from step S5 to the short-time suppression mode of step S6. Therefore, FIG.
Is executed, the control signal of the duty ratio initial value D1 is output in step S11, and step S12
Then, it is immediately reduced at a constant rate by a predetermined reduction amount ΔD, and when the duty ratio becomes 0% in step S13, the process ends and returns to the original state.

FIG. 6 shows the relationship between the duty ratio and the current supplied to the field coil. Therefore, under the condition of this small electric load, the switch unit 5 suppresses the power generation operation of the alternator 1 for a short time by the duty variable control signal as shown by the solid line in FIG. 7, and the engine load is reduced. This allows
The idling speed Nid is appropriately prevented from dropping and is kept at a constant speed, after which the power generation amount of the alternator 1 is gradually increased so as not to cause a shock.

If the voltage change amount ΔV is larger than the above with the electric load as shown by the broken line in FIG. 7, step S4
From step S7, the mode shifts to the medium time suppression mode. Therefore, the subroutine of FIG. 4 is executed. In this case, the control signal of the duty ratio initial value D1 is output in step S21, the control time t is initialized in step S22, and the control time t is counted in step S23. . And
The control time t is compared with the holding time ts1 in step S24, and when the holding time ts1 has elapsed, the process proceeds to step S25. Then, the duty ratio is reduced at a constant rate by the predetermined reduction amount ΔD, and when the duty ratio becomes 0% in step S26, the process ends and returns to the original. Therefore, under this medium electric load condition, the switch means 5 suppresses the power generation of the alternator 1 for the holding time ts1 by the duty control signal as shown by the broken line in FIG. 7, and at this time, the load of the alternator 1 is reduced in the engine. It is possible to suppress the output reduction. In this way, the suppression of the power generation of the alternator 1 is also controlled for a long time according to the increase of the electric load, similarly, the drop of the idling speed Nid is prevented, and thereafter the power generation state is smoothly returned so as not to cause a shock.

Further, when the voltage change amount ΔV is the largest together with the electric load as shown by the alternate long and short dash line in FIG. 7, step S3
To the long-time suppression mode in step S8. Therefore, the subroutine of FIG. 5 is executed, the control time t is initialized in step S31, the control signal of the duty ratio initial value D1 is output in step 32, and the control time t is counted in step S33. Then, step S34
The control time t is compared with the holding time ts2 at
When s2 has passed, the process ends and returns to the original state. Therefore, under the condition of this heavy electric load, the switching means 5 takes the longest time for suppressing the power generation of the alternator 1 by the pulse-like duty control signal as shown by the alternate long and short dash line in FIG. Therefore, the idling speed N when a large electric load is suddenly applied
The drop of id is effectively prevented.

On the other hand, during the power generation suppression control of the alternator 1, the control signal is prevented from being input to the idle control unit 23 to immediately open the idle control valve 22. For this reason, it is possible to prevent the intake air amount from being unnecessarily increased and the idling speed Nid to be increased.

The embodiments of the present invention have been described above, but the present invention is not limited to these.

[0017]

As described above, according to the present invention,
In the control system that controls the power generation of the alternator to prevent the engine speed from dropping during idling, etc., the control mode is set for each state of the electric load, and the power generation is suppressed and controlled by the duty control signal according to the control mode. Since it is configured like this, without sacrificing power generation excessively at each electric load, the engine speed drops optimally, unpleasant noise,
Vibration can be prevented. Since it is not necessary to increase the intake air amount when an electric load is applied, fuel consumption can be improved. Since a plurality of set values are provided and the control time is controlled so as to increase the power generation suppression time of the alternator in accordance with the decrease of the set values, it is possible to reduce the load when the engine is started and improve the startability. Since the configuration is such that the state of the electric load is determined by the voltage change of the battery, the control is simplified and the responsiveness is good.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a power generation control device for an alternator according to the present invention.

FIG. 2 is a diagram showing a flowchart of power generation control.

FIG. 3 is a diagram showing a flowchart of a short time suppression mode.

FIG. 4 is a diagram showing a flowchart of a medium time suppression mode.

FIG. 5 is a diagram showing a flowchart of a long time suppression mode.

FIG. 6 is a diagram showing a relationship between a duty ratio and an average current supplied to a field coil.

FIG. 7 is a diagram showing a time chart of power generation control.

[Explanation of symbols]

1 alternator 2 regulator 3 battery 5 switch means 10 control unit 11 Voltage change amount calculation unit 12 Control mode setting section 13 Control signal determination unit

Claims (3)

[Claims] 1. In a control system for generating power from an alternator according to a duty control signal from a control unit, the control unit includes a voltage change calculation means for calculating a voltage change amount of a battery within a minute time, and a control mode according to the voltage change amount. A control device for an alternator, comprising: a control mode setting unit that sets the control mode; and a control signal determination unit that outputs a duty control signal according to each control mode. 2. The alternator according to claim 1, wherein the control mode setting means sets a short time suppression mode, a medium time suppression mode and a long time suppression mode, respectively, according to the magnitude of the voltage change amount. Power generation control device. 3. The control signal determining means holds the duty control signal that decreases from the initial value at a constant rate in the short time suppression mode, holds the initial value for a constant time in the medium time suppression mode, and then keeps the constant value. The alternator power generation control device according to claim 1, wherein a duty control signal that decreases at a rate is output as a duty control signal that holds an initial value for a certain period of time in the long-time suppression mode and then returns.