JP2643601B2 - Idle rotation fluctuation control device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an idle rotation fluctuation control device for an engine that drives a generator by an internal combustion engine so as not to generate unpleasant vibration even when the electric load suddenly increases during idle operation. Things.

The present invention is useful when applied to, for example, a gasoline engine automobile.

BACKGROUND ART An automobile is provided with an alternator that is rotated and driven by an engine to generate power. While the engine is rotating, the electric power generated by the alternator is supplied to various electric loads, and the battery is charged with sufficient electric power.

In alternators, field coils (field coils)
Is rotated, a three-phase alternating current is generated in a stator coil provided in the stator. The three-phase alternating current is rectified by a three-phase bridge rectifier formed of six diodes and output as a direct current.

The voltage generated by the alternator is proportional to the rotation speed of the rotor and the magnitude of the exciting current (field current) flowing through the field coil. It is necessary to keep the voltage supplied to various electric loads and charging the battery constant, so if the rotation speed increases and the generated voltage exceeds the specified value, the regulator adjusts the field current to adjust the generated voltage. Control.

The regulator adjusts the value of the field current flowing through the field coil of the alternator according to the supply current to various loads. In the transistor type regulator, the amount of current is controlled by adjusting the duty ratio of the field current by turning on / off the power transistor. Thus, by adjusting the exciting current value with the regulator,
The voltage generated by the alternator is adjusted to prevent overcharging and overdischarging of the battery.

This regulator increases the field current flowing through the alternator when the electric load increases, and decreases the field current when the electric load decreases. Therefore, the torque required to rotationally drive the alternator increases when the electric load is large, and decreases when the electric load is small.

By the way, if the electric load suddenly increases while the engine of the automobile is idling, the field current flowing to the alternator increases, the torque for driving the alternator to rotate rapidly increases, the engine speed decreases, and in some cases, the engine speed decreases. It does not necessarily mean that the vehicle becomes unstable and does not cause unpleasant vibration to the driver.

During idle operation, the generated torque of the engine is small,
Particularly, when the idling rotational speed is set low for the purpose of reducing fuel consumption, the tendency described above may occur.

On the other hand, the driver does not perform any special operation during the idling operation, and also has low interior noise, which makes the driver sensitive to engine noise and rotation fluctuation. In such a case, if the electric load is increased by turning on the cooler or the like, the engine speed decreases, and this decrease in the engine speed is easily understood by the driver. When the driver feels that the idle speed has decreased, the driver tends to be uneasy or uncomfortable that a stall may occur. Further, when engine vibration occurs, anxiety and discomfort increase.

The present invention has been made in view of the above-described conventional technology, and provides an idle rotation fluctuation control device that limits the amount of decrease in the number of revolutions of an internal combustion engine even when the electric load increases rapidly during idle operation, and also prevents the battery from running up. Things.

DISCLOSURE OF THE INVENTION The present invention for solving the above-mentioned problem is different from the control of the idle speed by feedback to the intake system,
The idling operation of the engine is detected, and the amount of power generation of the generator at the start of the idling operation is detected using, for example, a field current as a parameter. Set as a value. As described above, when the upper limit value of the power generation amount is set in advance at the start of the idle operation of the engine, even if the electric load increases greatly during the idle rotation, the power generation at a certain value or more from the power generation amount at the start of the idle operation is limited. You. Therefore, the fluctuation of the torque required for driving the generator is also limited, and the decrease in the idle speed is suppressed to a small value. In addition, the amount of power generation is guaranteed up to the upper limit.
Therefore, there is no concern about overdischarging of the battery (battery exhaustion) when the electric load is slightly increased. The amount of decrease in the idling rotational speed corresponds to a value below the upper limit value and the amount of power generation at the start of idling operation, that is, a predetermined value. Therefore, the predetermined value for determining the upper limit value may be a value that can secure an “allowable minimum rotation speed” that does not cause unpleasant vibrations felt by the driver even when the engine rotation speed is reduced.

The upper limit value of the power generation amount does not necessarily have to be constant during the idling operation, and it is desirable that the upper limit value be gradually increased thereafter, or that the upper limit value be gradually reduced with a subsequent decrease in the electric load.

If the upper limit initially set during idling operation is gradually increased thereafter, the idling speed does not drop sharply even if the electric load increases, and the idle speed is controlled by feedback control to the intake system. A decrease in the number of revolutions is prevented. Further, since the upper limit gradually increases, for example, even if the idle operation continues for a long time and the electric load is considerably large during that time, the time for limiting the amount of power generation is reduced, and there is no worry about running out of the battery.

When the set upper limit value gradually decreases with a decrease in the electric load during the idling operation, the electric load substantially decreases once, and then substantially returns to the electric load at the start of the idling operation. However, even if there is a large increase in the electrical load, a sharp increase in the amount of power generation is limited. Therefore, a decrease in the idle speed is suppressed to a small value.

From the above, the idle rotation fluctuation control device of the present invention includes an engine, a generator driven by the engine,
A power generation parameter detecting means for detecting a parameter representing an actual field current of the generator; a means for detecting an idling operation of the engine; and a predetermined value based on a power generation amount represented by the detected parameter during the idling operation of the engine. And a field current limiter for limiting the field current of the generator in accordance with the set upper limit.

Preferably, the power generation parameter detecting means is a means for detecting, as a parameter, a ratio of the field current to the full power generation of the generator. Further, the above parameter is the on / off duty of the field current. Further, the above parameter is a time average of the on / off duty of the current and past field currents. More preferably, the power generation parameter detecting means is a means for obtaining a parameter by a primary filter process of an on / off duty of the field current. Furthermore,
The power generation parameter detecting means compares the on / off duty of the field current subjected to the primary filtering this time with a value obtained by adding a certain value to the on / off duty of the field current subjected to the previous primary filtering, and determines the smaller one as the parameter. It is a means to do. Still more preferably, the upper limit value setting means sets a duty obtained by adding a predetermined value to the field current duty detected as a parameter by the power generation parameter detecting means as an upper limit value, and the field current limiting means sets the duty equal to or less than the set duty. The duty of the field current of the generator.

Also preferably, the idle rotation fluctuation control device includes:
An idle speed control means is provided in the intake system of the engine and controls the amount of intake air. The predetermined value is set in accordance with an operation state of the idle speed control means.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an electric system of a gasoline engine automobile to which the present invention is applied, FIGS. 2 and 3 are flowcharts showing the operation of an embodiment of the present invention, and FIG. FIG. 5 is a circuit diagram showing a drive system of a gasoline engine automobile, and FIGS. 6, 7, and 8 are diagrams showing a relationship between an FR terminal duty and a G terminal ground duty. FIG. 9 shows alternator driving torque and FR
FIG. 4 is a characteristic diagram illustrating a relationship with a terminal duty.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows an electric system of a drive system of a gasoline engine automobile to which the present invention is applied, and FIG. 5 shows the drive system.

As shown in FIG. 5, air is sent to the engine 1 through an air cleaner 2 and an air supply pipe 3. A throttle valve 4 is attached in the middle of the air supply pipe 3, and the throttle valve 4 opens and closes in conjunction with an accelerator pedal (not shown). During the idling operation, the throttle valve 4 is fully closed, and the idle switch 5 detects this fully closed state (idling operation state). The bypass pipe 6 connects the distillation side and the downstream side of the air supply pipe 3 so as to bypass the throttle valve 4. A needle valve (bypass valve) 8 urged by a compression coil spring 7 is provided inside the bypass pipe 6, and the bypass pipe 6 is opened and closed by the needle valve 8 by the duty driving of the solenoid 9.

On the other hand, the alternator 10 is rotated and driven by the engine 1 to generate electric power, send electric power to various electric loads 11, and charge the battery 12 with surplus electric power. The battery 12 sends power to the electric load 11 when the power generated by the alternator is insufficient or power is not generated. The distributor 13 is provided with a crank angle sensor 14.

The electronic control unit 15 receives detection signals from various sensors such as the idle switch 5 and the crank angle sensor 14, and controls the solenoid 9 and each control device. In implementing the present invention, it plays a central role of control.

Next, the electric system will be described with reference to FIG. As shown in the figure, the alternator 10 mainly includes a power generation unit 10-1 having a stator coil SC and a field coil FC, a rectifier 10-2 formed of a diode, and a regulator 10-3. The regulator 10-3 changes the duty ratio of the field current flowing through the field coil FC in accordance with the voltage of the battery 12 and the used electric load capacity, thereby changing the value of the current generated by the generator 10-1. I am adjusting. That is, when the battery voltage decreases or the used electric load capacity increases, the duty ratio is increased to increase the generated current, and in the opposite situation, the duty ratio is decreased to reduce the generated current. .
Then, the duty ratio of the field current flowing through the field coil FC is detected by the electronic control unit 15 via the FR terminal at a certain cycle. Further, when the G terminal of the regulator 10-3 is grounded through the control unit 16 according to a command from the electronic control unit 15, the field current flowing through the field coil FC becomes zero, the generated current becomes zero, and the power generation is cut off. You. Although the regulator 10-3 adjusts the duty ratio according to the battery voltage and the used electric load capacity, the regulator of the type that adjusts the duty ratio based only on the used electric load capacity without referring to the battery voltage is used. There is also.

In FIG. 1, reference numeral 17 denotes an ignition switch,
18 is a charge lamp.

Next, a basic technique supporting an embodiment of the present invention will be described with reference to FIGS.

6 to 8 show the relation between the FR terminal duty and the G terminal ground duty. What is FR terminal duty?
Duty ratio (duty ratio) of field current detected by FR terminal
When the field current actually flowing through the field coil FC is continuous, the FR terminal duty is 10
0%, and the FR terminal duty becomes 0% when no field current flows through the field coil FC.
This FR terminal duty is proportional to the power generation rate of the alternator (the ratio of the actual power generation amount to the full power generation amount). G
The terminal grounding duty indicates a ratio of grounding the G terminal. When the G terminal is continuously grounded, the G terminal grounding duty becomes 100%, and when the G terminal is not grounded at all, the G terminal grounding duty becomes 0%. . When the G terminal is grounded as described above, power generation is forcibly cut off regardless of the control state of the regulator 10-3.

FIG. 6 shows the characteristics when the regulator 10-3 permits 100% power generation. It can be seen that as the G terminal ground duty is reduced, the FR terminal duty (power generation rate) increases. Fig. 7 shows that the regulator 10-3
This is a characteristic when the duty is limited to 50%, and it can be seen that the FR terminal duty (power generation rate) does not become 50% or more even when the G terminal grounding duty is 50% or less. FIG. 8 shows the characteristics when the regulator 10-3 limits the power generation to 25%.
It can be seen that the terminal duty (power generation rate) does not exceed 25%. From the above, it can be concluded that "the maximum value of the FR terminal duty (power generation rate) can be controlled by controlling the G terminal grounding duty or the opposite non-grounding duty of the G terminal". That is, it is possible to set the upper limit of the power generation amount.

FIG. 9 shows the relationship between the FR terminal duty (power generation rate) and the driving torque required to rotationally drive the alternator. "The FR terminal duty (power generation rate) and the alternator driving torque have a one-to-one relationship. Something is ".

From the conclusions obtained from FIG. 6 to FIG. 9, the following findings were found. That is, when the electric load increases, the regulator generally controls so as to increase the power generation rate, and when the power generation rate increases, the alternator driving torque increases (see FIG. 9). It causes vibration. Therefore, during idling, the upper limit of the power generation rate is limited by the G terminal grounding duty or the reverse non-grounding duty (see FIGS. 6 to 8), and if the alternator driving torque is limited, the engine speed becomes a certain speed. This does not cause the occurrence of unpleasant vibration. Further, if the upper limit is set to a strict value, even if the electric load suddenly increases during idling, the driver does not recognize that the engine speed has decreased. When the power generation rate is limited, the power becomes insufficient for the sudden increase in the electric load, but the shortage is covered by the battery.

Next, an embodiment of the idle rotation fluctuation control of the present invention performed by the electronic control unit 15 as the center of the control will be described with reference to FIGS.
This will be described with reference to FIGS. 2 and 3 show the flow of the operation, and FIG. 4 explains the upper limit.

Here, the non-grounding duty of the G terminal (DG)
The following description is based on the assumption that the power generation amount is controlled by the following.

In FIG. 2, the crank pulse interrupt timer interrupt or engine, the FR terminal on the (field current F _r energized) time integrated by the counter of the electronic control unit 15 (step S1), the respective crank from the sensor 14 when the 180 ° signal up standing, the actual duty ratio i.e. F _r duty instantaneous value of the oN counter field current F _r (DFRR) (step S2, S3).

DFRR = (F _r on integration time) / A (crank angle of 180 intervals of the rising time of the DEG signal) Basically, the F _r Duty (DFRR) and the field current ratio, etc. field current actual for full power generation Power generation control is performed using the detected value of the power generation amount. However, in the present embodiment, the power generation amount fluctuates from moment to moment, so if it is directly affected by this fluctuation, it is not good for the load fluctuation or the charge / discharge cycle of the battery. I have. The average power generation is a simple average within a certain time,
Anything such as a weighted average like a primary filter may be used.

In step S4, the average F _r which represents the average power generation amount of time
The duty (DFR _i ) is determined by the following primary filter operation. DFR _i-1 is the duty of the previous average F _r.

DFR _i = α · DFR _i−1 + (1−α) DFRR where α is a filter gain, 0 <α <1, and 0.
A value larger than 5 is preferable, for example, 0.75.

If the current idle control is being performed based on the ON signal from the idle switch 5 (step S5), the electronic control unit 15 sets the current target in step S6 (FIG. 3).
F _r Duty a (DFROBJ _i) determined by the following equation.

_{DFROBJ i = min (DFR i,} DFR i-1 + β) That, and the current average F _r duty DFR _i, the average of the last time
F _r Duty DFR _i-1 of the value obtained by adding a small amount of β to the smaller for safety and the present target F _r duty.
The minute amount β is, for example, 0.4%.

The Ke becomes idle control in, uniformly the target F _r duty, and DFROBJ = 100% (Step S7).

Then, in the next step S8, the electronic control unit 15 determines the non-grounding duty DG of the G terminal, which determines the upper limit of the current power generation amount, as the field control target duty by the following equation, and executes power generation control (step S9).

DG = DFROBJ + ΔG where DG ≦ 100%. ΔG is a predetermined value of a small value such as 4% or 10%, and is set to a value such that idle control by feedback to the intake system, that is, ISC (idle speed control) can be followed. Further, the relationship between β and ΔG is β <ΔG, for example, β is ΔG
About 10% of G is preferable.

In the above control, as can be seen from the operation of step S8, the upper limit value (DG) of the power generation amount increases or decreases every time the crank angle 180 ° signal rises. And the power generation control may be performed.

Further, in the above-described embodiment, the idle rotation fluctuation control device of the present invention is implemented using the electronic control device 15, but the present invention may be implemented using a dedicated controller. May be built in the alternator. Further, the engine speed may be obtained by multiplying the alternator speed by a required number.

In addition, the determination conditions at the start of the idling operation include that the transmission select switch 19 shown in FIG.
The switch 20 may detect that the clutch is disconnected.

Further, although the upper limit of the power generation amount is set and changed by the non-ground duty DG of the G terminal, the reverse ground duty may be used, and the applied voltage to the S terminal of the voltage regulator 10-3 is substantially adjusted. To the field coil
Any means that can set and change the upper limit of the FC excitation current may be used.

INDUSTRIAL APPLICABILITY According to the present invention, as described above in detail with the embodiment, even if the electric load suddenly increases during the idling operation, the upper limit value of the power generation amount of the generator is set during the idling operation. Therefore, the torque required to rotate the generator does not exceed a certain value, so that the engine speed does not decrease so much and unpleasant vibrations do not occur by the engine.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-57-193947 (JP, A) JP-A-58-192500 (JP, A) JP-A-62-152400 (JP, A) JP-A 62-152400 95935 (JP, A) JP-A-62-110445 (JP, A) JP-A-59-59099 (JP, A)

Claims (8)

(57) [Claims] An engine, a generator driven by the engine, power generation parameter detecting means for detecting a parameter representing an actual field current of the generator, means for detecting an idling operation of the engine, Upper limit value setting means for setting, as an upper limit value of the power generation amount, a value larger than the power generation amount represented by the detected parameter during the idling operation of the engine, and restricting the field current of the generator according to the set upper limit value An idle rotation fluctuation control device comprising: 2. The idle rotation fluctuation control device according to claim 1, wherein said power generation parameter detecting means is means for detecting, as a parameter, a ratio of a field current to full power generation of the generator. 3. The idle rotation fluctuation control device according to claim 2, wherein said parameter is an on / off duty of a field current. 4. The idle speed fluctuation control device according to claim 3, wherein said parameter is a time average of on-off duty of current and past field currents. 5. An idle speed fluctuation control device according to claim 4, wherein said power generation parameter detecting means is means for obtaining a parameter by a primary filter processing of an on / off duty of a field current. 6. The on / off duty of a field current which has been subjected to primary filtering this time by said power generation parameter detecting means,
6. The idle rotation fluctuation control device according to claim 5, wherein said means is a means for comparing a value obtained by adding a certain value to the on / off duty of the field current which has been subjected to the primary filtering last time, and using the smaller value as a parameter. 7. The upper limit value setting means sets a duty obtained by adding a predetermined value to a field current duty detected as a parameter by the power generation parameter detecting means as an upper limit value, and the field current limiting means sets the duty equal to or less than the set duty. 7. The idle rotation fluctuation control device according to claim 6, wherein the duty of the field current of the generator is limited. 8. The idle speed fluctuation control device is provided in an intake system of an engine, and comprises idle speed control means for controlling the intake air amount. The predetermined value is determined based on a work situation of the idle speed control means. 2. The idle speed fluctuation control device according to claim 1, wherein the idle speed fluctuation control device is set according to the conditions.