JP2903683B2 - Vehicle idle speed control device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle idle speed control device that monitors the power generation state of a vehicle generator and changes the idle speed.

2. Description of the Related Art Conventionally, it has been known that an idle rotation speed of a vehicle may be reduced as much as possible in order to improve fuel efficiency of the vehicle.

However, when the idling rotational speed is reduced, the output torque of the engine decreases, and the idling rotational speed easily fluctuates or the engine stalls easily in response to fluctuations in the engine load.

Therefore, as a technique for solving the above problems, Japanese Patent Application Laid-Open
The technique disclosed in JP-A-59-158357 is known. This technology monitors the power generation state of a generator and controls the idle rotation speed so that the power generation capacity of the generator is always as close as possible to 100%. With this technology, by securing the output of the generator required for the electric load, and by reducing to the minimum required idle speed,
Fuel efficiency can be improved.

[Problems to be Solved by the Invention] However, according to the prior art, when an intermittent electric load such as a wiper or a hazard is activated, a generator output changes in accordance with a change in power consumption, and an idle rotation speed changes. . As a result, during the operation of the intermittent electric load, the idle rotation speed fluctuates according to the ON-OFF operation of the intermittent electric load.

In addition, when the output change of the generator is averaged by an integrating circuit to suppress the change of the idle speed, the idle speed is set so that the power generation capacity of the generator is as close as possible to 100%. The output torque of the engine is small because it is lowered to the necessary minimum value and stabilized. For this reason, when the intermittent electric load operates, the idling rotational speed fluctuates due to the torque load fluctuation of the generator, and there is a problem that an engine stall occurs in some cases.

An object of the present invention is to provide a vehicle idle speed control device that suppresses fluctuations in idle speed during operation of an intermittent electric load.

[Means for Solving the Problems] In order to achieve the above object, a control device for a vehicle idle speed according to the present invention employs technical means shown in FIG.

The idle rotation speed control device includes an excitation coil 1a that is energized to form a magnetic field, and an armature coil 1b that generates an electromotive force by a change in a magnetic field generated by the excitation coil 1a.
A generator 1 in which a magnetic field change is given to the armature coil 1b by driving the excitation coil 1a or the armature coil 1b by the engine 2, and charged by the power generated by the generator 1. Battery 3
And an intermittent electric load 4 operated by the electric power generated by the generator 1 or the electric power charged in the battery 3.
A switching element 5a for interrupting the current flowing through the exciting coil 1a, and changing the duty ratio of the switching element 5a in accordance with the state of charge of the battery 3 to maintain the charging capacity of the battery 3 within a predetermined range. Regulator 5
A rotation speed varying means 6 for changing an idle rotation speed of the engine 2, and when the intermittent electric load 4 is not operating, the duty ratio of the switching element 5 a is set to a predetermined upper limit and a lower limit. Non-intermittent control means 7a for controlling the idling rotational speed so as to be within a first target duty ratio range between the first target duty ratio and the duty ratio of the switching element 5a when the intermittent electric load 4 is operating. However, the control circuit 7 includes an intermittent-time control means 7b for controlling the idle rotation speed so as to be equal to or less than a second target duty ratio which is equal to or less than the upper limit of the first target duty ratio range.

[Operation] a) When the intermittent electric load is not operating, the non-intermittent control means of the control circuit changes the rotation speed so that the duty ratio of the switching element falls within a first target duty ratio range set in advance. Means for controlling the idle speed.

That is, when the generator is required to have a large power generation capacity, the idle rotation speed is increased so that the switching element generates a large amount of power within the first target duty ratio range. Conversely, when a small power generation capacity is required for the generator, the idling speed is reduced so that the duty ratio of the switching element generates a small amount of power within the first target duty ratio range.

B) When the intermittent electric load is operating, the intermittent control means of the control circuit controls the rotation speed such that the duty ratio of the switching element is equal to or lower than the second target duty ratio which is equal to or lower than the upper limit of the first target duty ratio range. The idle speed is controlled by controlling the variable means.

That is, when the intermittent electric load is turned on and the generator is required to have a large power generation capacity, the idle rotation speed is increased to make the duty ratio of the switching element equal to or less than the second target duty ratio. Next, even if the intermittent electric load is turned off and the generator is required to have a small power generation capacity, and the duty ratio of the switching element decreases,
Since the duty ratio of the switching element is equal to or lower than the second target duty ratio, the idle rotation speed does not decrease and remains high. When the intermittent electric load is turned on again, the idle rotation speed is high and the duty ratio of the switching element is equal to or lower than the second target duty ratio, so that the idle rotation speed remains high. In this way, the fluctuation of the idle speed during the operation of the intermittent electric load is suppressed.

Further, even when a circuit for averaging the output change of the generator is provided, the average idle rotation speed increases and the output torque of the engine increases during the operation of the intermittent electric load. For this reason, even if the torque load of the generator changes due to the operation of the intermittent electric load, the fluctuation of the idling rotational speed can be suppressed as compared with the related art.

[Effects of the Invention] As shown in the above operation, the present invention can reduce the fluctuation range of the idle rotation speed at the time of operation of the intermittent electric load, as compared with the related art, Fluctuation of generated engine noise and engine vibration is suppressed. As a result, the livability of the vehicle can be improved.

[Embodiment] Next, a control apparatus for a vehicle idle rotation speed of the present invention will be described based on an embodiment shown in the drawings.

(Structure of Embodiment) FIGS. 2 to 5 show an embodiment of the present invention.
FIG. 2 is a schematic block diagram of a control device for a vehicle idle speed.

The automobile includes an electric load 10 having a substantially constant power consumption, such as a sidelight, a headlight, and a radio, and an intermittent electric load 11, such as a direction indicator lamp and an intermittent wiper, whose power consumption periodically changes. And the car has the electric load 10 and the intermittent electric load
A battery 12 for supplying electrodes to 11 is mounted. The battery 12 is charged by a generator 14 which is driven by a vehicle driving engine 13 to generate power.

The generator 14 includes an excitation coil 15 that is energized to form a magnetic field.
And an armature coil 16 that generates an electromotive force by a change in a magnetic field generated by the excitation coil 15.
Alternatively, one of the armature coils 16 is rotationally driven by the engine 13. The AC current generated by the armature coil 16 is converted into DC by the rectifier circuit 17 and then converted to DC.
Output to 10, intermittent electric load 11, and battery 12.

The amount of power generated by the generator 14, that is, the amount of power generated by the armature coil 16 is determined by the rotational drive speed of the generator 14 and the amount of power supplied to the exciting coil 15. The energization amount of this exciting coil 15 is
Controlled by the regulator 18.

The regulator 18 includes a switching element 19 for interrupting the current supplied to the exciting coil 15. The switching element 19 according to the present embodiment uses a semiconductor such as an FET or a bipolar transistor, and is turned on / off in accordance with the energized state of the gate and the base, and controls the current supplied to the exciting coil 15.

The regulator 18 detects the voltage of the battery 12, compares the detected battery voltage with a reference voltage, and generates a signal for increasing the duty ratio of the switching element 19 when the battery voltage is lower than the reference voltage. is there.

Further, the automobile includes a vehicle idle speed control device 20 that controls the idle speed of the engine 13 according to the duty ratio of the switching element 19. This control device 20
Is composed of a control circuit 21 using a microcomputer, and a speed varying means 22 for changing an idle rotation speed of the engine 13 according to a signal of the control circuit 21.

The control circuit 21 includes an operation program for a non-intermittent control unit 23 that operates when the intermittent electric load 11 is not operating, and an intermittent control unit 24 that operates when the intermittent electric load 11 operates.

The non-intermittent control means 23 detects the duty ratio of the switching element 19, and detects the detected duty ratio in a first preset.
The idling rotational speed is changed by controlling the speed varying means 22 so as to fall within the target energization rate range (for example, the upper limit is 90%, the lower limit is 70%, and is within the oblique line in FIG. 3). That is, when the detected duty ratio is higher than the upper limit of the first target duty ratio range, the idle rotation speed is increased to bring the duty ratio into the first target duty ratio range. Is a control means for lowering the idle rotation speed so that the duty ratio falls within the first target duty ratio range when is lower than the lower limit of the first target duty ratio range.

The intermittent-time control means 24 detects the duty ratio of the switching element 19, and controls the idle rotation so that the detected duty ratio becomes equal to or lower than a second target duty ratio set lower than the upper limit of the first target duty ratio range. In the present embodiment, the speed is controlled, and the term “below the second target duty ratio” in the present embodiment is set to be equal to or lower than the lower limit of the first target duty ratio (the duty ratio is equal to or less than 70%, and is in the oblique line in FIG. 4). That is, when the detected duty ratio is higher than the second target duty ratio, the control unit increases the idle rotation speed and maintains the idle rotation speed at the rotation speed even if the detected duty ratio decreases. is there.

The speed varying means 22 is an electromagnetic actuator (not shown)
Is used to change the intake air amount of the engine 13 and the throttle opening to change the idle rotation speed of the engine 13.

Next, an example of the operation of the non-intermittent control means 23 and the intermittent control means 24 programmed in the control circuit 21 will be described as a fifth example.
This will be described with reference to the flowchart of FIG.

First, in step S1, it is determined from the throttle opening and the vehicle speed whether or not the engine 13 is in an idle state. If this determination is NO, the process returns to step S1.
If the determination result is YES, in step S2,
The duty ratio C of the switching element 19 is read. Subsequently, in step S3, it is determined whether or not the intermittent electric load 11 is operating.

If the determination result of step S3 is NO, step S4
In, it is determined whether or not the duty ratio C of the switching element 19 is higher than the upper limit C _{MAX of} the first target duty ratio range.
If the result of this determination is YES, in step S5, a signal for increasing the idling rotational speed by a predetermined amount (for example, 10 rpm) is output to the speed varying means 22, and the routine returns. If the determination result in step S4 is NO, in step S6, it is determined whether or not the duty ratio C of the switching element 19 is lower than the lower limit C _{MIN of} the first target duty ratio range. If the result of this determination is YES, in step S7, a signal for lowering the idle rotation speed by a predetermined amount (for example, 10 rpm) is output to the speed variable means 22, and the routine returns. Note that step
If the determination result in S6 is NO, since the duty ratio C of the switching element 19 is within the first target duty ratio range, there is no need to change the idle speed, and the routine returns.

On the other hand, if the decision result in the step S3 is YES, a step S8 sets the duty ratio C of the switching element 19 to the second
It is determined whether it is higher than the target energization rate C _MIN . If the result of this determination is YES, the operation proceeds to step S5, where the idle speed is increased by a predetermined amount. If the determination result of step S8 is NO, the duty ratio C of the switching element 19 becomes the second
Since the duty ratio is equal to or less than the target energization rate, there is no need to change the idle rotation speed, and the routine returns.

(Operation of Embodiment) The operation of the above-described vehicle idle speed control device 20 will be briefly described with reference to the graphs of FIGS. 3 and 4.

○ When the intermittent electric load 11 is not operating.

When the electric load 10 (for example, a headlight) is turned on when the power output of the generator 14 is a1 and the idling rotational speed is a2 at the time of idling of the vehicle and the state is indicated by a point a in the graph, the generator
The power generation output of 14 becomes b1. Then, the non-intermittent control means 23
, The point a in the graph shifts to the point b, and the idle rotation speed increases to b2.

Conversely, when the headlight is turned off, the power output of the generator 14 becomes a
Becomes 1. Then, by the operation of the non-intermittent control means 23, the point b in the graph shifts to the point b, and the idle rotation speed decreases to a2.

○ When the intermittent electric load 11 is operating.

When the vehicle is idling, the power output of the generator 14 is c1, the idling rotational speed is c2, and in the state shown at the point c in the graph, the intermittent electric load 11 (e.g., hazard) is activated and the hazard is turned on. When the power output of the machine 14 becomes d1, the point c in the graph is changed to the point d by the operation of the intermittent control means 24.
Then, the idle speed increases to a2.

If the hazard turns off while the hazard is active, the generator 1
The power generation output of 4 becomes c1. As the power output of the generator 14 decreases to c1, the duty ratio of the switching element 19 decreases. However, even if the duty ratio decreases, the reduced duty ratio is equal to or less than the second target duty ratio, and the point d in the graph shifts to the point e. As a result, the idling rotational speed does not change and is kept at d2.

When the hazard is turned on again, the power output of the generator 14 becomes d1, and the point e in the graph shifts to the point d. However, the idle speed does not change and is kept at d2.

When the operation of the hazard stops, the point d or the point e shifts to the point c (within the first target duty ratio range) by the operation of the non-intermittent control means 23, and the idle speed decreases to c2.

(Effects of the embodiment) As shown in the above operation, this embodiment has the intermittent electric load.
When 11 is not operating, unnecessary idle rotation can be reduced, and fuel efficiency of the vehicle can be improved.

In addition, when the intermittent electric load 11 is operating, the idling rotational speed increases and does not fluctuate even if the intermittent electric load 11 repeats ON-OFF. Note that the torque load of the generator 14 fluctuates due to the ON-OFF of the intermittent electric load 11,
During the operation of the intermittent electric load 11, the idling speed increases and the output torque of the engine 13 increases, so that the operation of the intermittent electric load 11 causes a torque load fluctuation on the generator 14. Even if it occurs, the fluctuation of the idle speed can be suppressed as compared with the conventional case.

As a result, fluctuations in engine sound and engine vibration generated when the intermittent electric load 11 is operated are suppressed as compared with the related art,
The livability of the vehicle is improved.

Note that the numerical values shown in the embodiments are for explanation, and the present invention is not limited to the numerical values of the embodiments.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an outline of the present invention. 2 to 5 show the present embodiment, and are schematic block diagrams of the control device for the idling speed of the vehicle shown in FIG. 2,
FIGS. 3 and 4 are graphs showing the relationship between the engine speed and the duty ratio of the exciting coil with respect to the generator output.
FIG. 5 is a flowchart showing the operation of the control circuit. In the figure, 1a ... exciting coil, 1b ... armature coil, 1 ... generator, 2 ... engine, 3 ... battery, 4 ... intermittent electric load, 5a ... switching element, 5 ... regulator, 6 ... Rotation speed variable means, 7a ... non-intermittent control means, 7b ... intermittent control means, 7 ... control circuit

Claims (1)

(57) [Claims] (A) An excitation coil that is energized to form a magnetic field, and an armature coil that generates an electromotive force by a change in a magnetic field generated by the excitation coil, wherein the excitation coil or the armature coil is driven by an engine. (B) a battery charged by the power generated by the generator; and (c) a power generated by the generator. Alternatively, an intermittent electric load operated by electric power charged in the battery; and (d) a switching element for interrupting a current flowing through the exciting coil, wherein a duty ratio of the switching element is changed according to a state of charge of the battery. (E) changing the idling speed of the engine by maintaining the charging capacity of the battery within a predetermined range. (F) (f-1) when the intermittent electric load is not operating, the duty ratio of the switching element is set to a first target energization between an upper limit and a lower limit set in advance. A non-intermittent control means for controlling an idle rotation speed so as to fall within a rate range; and (f-2) when the intermittent electric load is operating, the duty ratio of the switching element is the A control circuit including intermittent control means for controlling an idle rotation speed so as to be equal to or lower than a second target duty ratio that is equal to or lower than an upper limit of one target duty ratio range.