JPH0650196A - Control device for number of idle revolutions of engine - Google Patents

Abstract

PURPOSE:To prevent the fluctuation of the number of revolutions of an engine even when an electric load, such as a light for a vehicle, is turned ON and OFF during idle running of an engine. CONSTITUTION:A generation demand signal 1 to an alternator ALT is outputted in response to an electric load L connected to the alternator ALT together with a battery B. When the signal 1 is changed by a given value or more, the opening of an ISC valve is controlled by means of a computer CNT. After a lapse of a delay time in which an air amount responding to a current electric load can flow in through the control thereby, a field current 2 having a value corrected according to the signal 1 is fed to a field coil FC.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine idle speed control device, and more particularly to an idle speed control when an alternator driven by an engine is subjected to an electric load such as a vehicle light, a heat ray or a power window. Regarding the device.

[0002]

2. Description of the Related Art Conventionally, in this type of idle speed control device, the electric load applied to the alternator is determined from a signal (eg, generated voltage) from the alternator or an on / off signal of each electric load switch. It is configured to read and correct the opening degree of the engine idle speed control valve (hereinafter referred to as ISC valve) according to the load state at that time.

However, even if the electric load applied to the alternator is increased to control the opening of the ISC valve, the opening of the ISC valve is actually increased and the ISC valve is opened.
Since there is a certain delay until the amount of air flowing into the SC valve increases, in reality, after the load of the alternator is applied to the engine (depending on the electrical load being applied at that time, Since the amount of power generated by the alternator is increased by increasing the field current supplied to the field coil, a load (torque) is applied to the engine that drives the alternator, and such a load is applied. Later), the IS
The air for idle-up as described above flows into the C valve. That is, when the electric load is applied, the alternator has already started to generate electric power corresponding to the electric load and applies a load to the engine, and the increase in the ISC valve opening cannot be in time. Therefore, there is a problem that the amount of air is insufficient at the moment when the electric load is applied, and the engine speed decreases. On the contrary, when the electric load is cut off, due to the same time delay as above,
There was a problem that the engine speed increased too much and the fuel consumption was adversely affected.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and the engine speed when the electric load such as the above-described vehicle light is turned on or off during idle operation of the engine. It is intended to improve the engine stalling resistance and fuel efficiency by eliminating the decrease and abnormal increase in the engine.

[0005]

According to the present invention, in order to solve such a problem, a power generation request signal is output to an alternator driven by an engine according to an electric load connected to the alternator together with a vehicle battery. Means, means for controlling the opening of the idle speed control valve when the output power generation request signal changes by a predetermined value or more, and a predetermined delay time is set from the time when the opening of the idle speed control valve is controlled And a means for supplying the field coil of the alternator with a field current having a value corrected according to the power generation request signal after the time set by the delay time setting means has elapsed. An idle speed control device is provided.

Here, the power generation request signal (for example, a regulator section connected to the output side of the alternator as described later, is taken in as a pulse signal of a variable duty value to a computer for controlling the ISC valve opening. Is changed by a predetermined value or more, the ISC valve opening can be controlled to be corrected by a predetermined value. Also I
The opening degree of the SC valve is variably controlled according to the engine speed and the value of the power generation request signal, so that the opening degree can be corrected according to the electric load.

[0007]

According to the above construction, when the electric load is turned on or off during the idling operation of the engine, the ISC valve opening degree is set in advance so that the engine speed becomes the target speed at that time. Feedback control, and by the control of the ISC valve opening, the power generation control for the alternator is performed after the elapse of a predetermined delay time in which an air amount corresponding to the electric load amount at that time can be used for combustion. Based on the power generation request signal, a feed current (a pulse signal having a variable duty value) supplied to the field coil of the alternator is corrected to start. In this way, the prospective control of the ISC valve opening degree is performed before the load is applied to the engine, so that it is possible to prevent the engine speed from fluctuating or stall even when the electric load is turned on or off. it can.

Further, in this case, the opening of the ISC valve is variably controlled according to the engine speed and the value of the power generation request signal to the alternator, so that the opening of the ISC valve based on the electric load is controlled. It is possible to completely separate the correction from the basic correction of the ISC valve opening when there is no load. Therefore, even if the electric load state at that time is changed variously, the electric load at that time (alternator load)
The ISC valve opening can be corrected in accordance with the above condition, and thus the engine stall resistance and the stability of the engine speed can be further improved.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the overall construction of an idle speed control device as an embodiment of the present invention, and FIG. 2 is a timing chart for explaining the operation of the device. In FIG. 1, ALT
Is an alternator driven by an engine,
AC is a power-generating coil, FC is a magnetic field excited by a battery B (as will be described later, the strength of the magnetic field is controlled according to the load condition via a regulator unit RG and an engine control computer CNT). is there. The three-phase AC voltage generated in the electromotive coil AC is rectified by the diodes D1 to D8, and the battery B is charged by the rectified voltage via the regulator section RG. Further, a load L (including an air conditioner described later and various electric loads such as the above-described vehicle light) is connected in parallel with the battery B. The regulator R
In addition to the illustrated IC regulator, G is composed of transistors T1 and T2 externally attached to the IC regulator, a capacitor C, a diode D, and the like. Also S
W1 is a load switch (actually, provided for each load connected in parallel, for example), SW2 is an ignition switch, and LP is an indicator lamp.

The engine idle speed control valve (I
Engine control computer C for controlling the opening of SC valve)
The engine speed, the ON / OFF signal from the neutral switch, the ON / OFF signal from the air conditioner, the engine water temperature signal, etc. are taken into the NT, and the engine such as the ON / OFF signal of the neutral switch and the air conditioner and the engine water temperature is taken in. The target rotation speed at the time of idling, which is determined according to the state, is stored in the computer CNT,
The ISC valve opening is controlled so that the engine speed becomes the target speed at that time.

Here, the regulator section R of the alternator
G is the route in FIG. 1 from the F terminal of the regulator unit RG to the engine control computer CNT according to the voltage change of the battery that changes according to the state of the load connected in parallel with the battery B. Through, a power generation request signal (pulse signal) having a variable duty value (for example, the duty value increases as the load increases as shown in (1) of FIG. 2) is output. Then, in the engine control computer CNT, the magnitude of the electric load at that time is obtained from the output duty value from the F terminal, and the output duty value has a certain value (for example, in FIG. (1) is larger than a (%)), the electric load judgment flag is switched from OFF to ON as shown in (2) of FIG. 2 and shown in (3) of FIG. As shown in Fig. 2, first, the control is performed to increase the opening of the ISC valve by an amount corresponding to the electric load (in (3) of Fig. 2, the output duty value to the ISC valve is b (%) only. Increased is shown). The ISC whose opening is increased by the above control
At the timing when the air increased in quantity through the valve flows into the combustion chamber (at the timing delayed by d milliseconds after the control of the output duty value to the ISC valve as shown in FIG. 2), 4) From the engine control computer CNT to the feed coil FC of the alternator as shown in FIG.
A field current whose on-time (duty value) is corrected to be increased according to the output duty value from the F terminal is supplied, whereby the power generation amount of the alternator is increased. On the contrary, when the electric load is turned off, first, the opening degree of the ISC valve is controlled to be reduced by the turned off electric load, and then (after the delay time as described above), The alternator is supplied with a normal (that is, the duty value is corrected to decrease) field current.

FIG. 3 is a process performed by the engine control computer CNT to determine an electric load correction value DB of ISC valve opening shown in FIG. 7 which will be described later when the electric load applied to the alternator increases. The procedure is illustrated by a flow chart, and in step 1, it is assumed that the output duty value of the power generation request signal output from the F terminal of the regulator unit RG is such that the electric load enters as shown in FIG. 2 (1). Predetermined threshold value a
It is determined whether or not it has increased by (%) or more. If the result is No, the process proceeds to step 2, the delay counter CDU is cleared, and the electric load correction value DB is set to 0 in step 3, but in the case of Yes. Goes to step 4, and a predetermined electric load increase amount (corresponding to the ISC valve opening increase amount) b is set as the electric load correction value DB. When the process proceeds to step 4, the delay counter CDU remains on.

Next, FIG. 4 is a flow chart illustrating a processing procedure performed by the engine control computer CNT to determine the ON output to the field coil shown in FIG. In the main routine, in step 11, the reference duty value DUB of the field current supplied to the field coil under no load is calculated from the engine speed at that time, and in step 12, the reference duty value DUB is calculated from the F terminal of the regulator unit. Based on the output duty value of the power generation request signal taken through the route of, the corrected duty value (increases according to the load applied at that time) DUH proportional to the output duty value is calculated. Next, at step 13, it is judged if the count value of the delay counter CDU has reached the delay time d milliseconds or not, and if it is no, the routine proceeds to step 14 where the final duty value of the field current is the reference value. Duty value DUB
If the answer is YES (when the delay time d milliseconds is reached), the process proceeds to step 15 where the final duty value of the field current is (DUB + D).
UH).

Next, in the routine executed every 4 milliseconds shown in FIG.
Alternatively, the time for which the field current (pulse current) is kept on is calculated based on the final duty value set in step 15, and is supplied to the field coil through the route of FIG. 1 in step 17. Immediately turn on the field current (pulse current). Next, in step 18, the time after the ON time calculated in step 16 has elapsed from the turned-on time (current time) is set in the compare register provided in the computer CNT, and in step 19 The field current is also set to OFF in the compare register. As a result, the field current is turned off when the time set in the compare register matches the elapsed time of the timer provided in the computer CNT.

5 to 8 show the IS shown in FIG.
The processing procedure performed by the engine control computer CNT for controlling the opening degree of the C valve is illustrated by a flow chart. First, in FIG. 5, in step 21, it is determined whether or not the engine is stopped. If there is, the ISC valve opening is set to 0% in step 22. If the result is No, the process proceeds to step 23 and the test mode (I
If the operation of the SC valve is checked), the ISC valve opening is set to 50% in step 24. If the determination in step 23 is no, the process proceeds to step 25 and I
SC valve opening calculation timing (The timing for calculating the ISC valve opening according to the load state at that time is, for example, 180 °
It is determined whether it is CA), and if YES, the process proceeds to step 26.

Then, in step 26, the opening correction value (starting correction amount) D immediately after the engine startup is started.
STA is calculated, in step 27, an opening correction value (water temperature correction amount) DTHW for increasing the engine speed during warm-up operation in cold weather is calculated, and in step 28, the engine during racing or deceleration is calculated. Opening correction value (engine stall prevention correction amount) to prevent the rotation speed from falling.
DDN is calculated, an opening degree correction value (dashpot correction amount) DDP for improving drivability at the time of acceleration is calculated in step 29, and further, in step 30, the engine speed when the N range is shifted to the D range is calculated. An opening degree correction value (ND shift correction amount) DE for compensating for a drop or a D range load (due to the transmission torque) is calculated.

Next, the routine proceeds to step 31 in FIG. 6 to calculate the target engine speed at the time of idling corresponding to each load, and the target engine speed is obtained according to the difference between the target engine speed and the engine engine speed at that time. Thus, the ISC valve opening is feedback-controlled. Next, at step 32, it is judged if the air conditioner is on, and if yes, step 33
In step 34, feedback control is performed so that the target rotation speed is reached when the air conditioner is turned on. In step 34, the ISC valve opening X (%) for setting the target rotation speed is (DAC + DG) (where DG is the target rotation speed). It is set from the learning value to reach the number faster). On the other hand, if the determination in step 32 is NO, feedback control is performed in step 35 so that the target rotation speed when the air conditioner is off, and further predetermined learning control is performed in step 36, and then step 37 is performed. The ISC valve opening X (%) for setting the target speed at the time of OFF is set to DI.

Next, in step 38 of FIG. 7, the IS
As the C valve opening X (%),
A value (X + DSTA + DTHW +) obtained by adding each correction value calculated in steps 26 to 30 to X set in (on) or step 37 (when air conditioner is off).
DDN + DDP + DE) is set. Further step 3
In step 9 of FIG. 3 (when the electric load such as the above-described vehicle light is not applied so much) or in step 4 (when the electric load is applied, the output duty value output from the F terminal is a. (When increased by (%) or more), the electric load correction value DB set is calculated (in the example shown in FIG. 3, the value of the DB is 0 (step 3) or b (step 4)), and 40 at the ISC
As the valve opening X (%), X set in step 38 above
Value obtained by adding DB calculated in step 39 to (X +
DB) is set. When it is determined in step 41 that the fuel cut control is being performed, the ISC valve opening X is set to DFC (a value necessary for preventing engine stall upon recovery from fuel cut and improving drivability) in step 42. However, as long as the determination in step 41 is NO, the ISC valve opening set in step 40 is used.

Then, in the routine executed every 4 milliseconds shown in FIG. 8, in step 46, the ISC valve opening X (%) set in step 40 or 42 is set to the ISC valve. Of the control pulse signal is calculated, and the control pulse signal output to the ISC valve is immediately turned on in step 47. Next, in step 48, the time after the ON time calculated in step 46 has elapsed from the turned-on time (current time) is set in the compare register, and in step 49 the ISC valve control is performed in the compare register. It also sets the output off. As a result, the ISC valve control output is turned off when the time set in the compare register matches the elapsed time of the timer provided in the computer CNT.

In the above embodiment, the electric load correction value DB of the ISC valve opening is the electric power generation request signal output from the F terminal of the regulator section (the duty value increases as the electric load increases. ) Is greater than or equal to a predetermined value (for example, a
Although it is set so that it becomes the predetermined value b when it increases (in (%) or more), in the present invention, the electric load correction value DB of the above ISC valve opening is the engine speed and the value of the power generation request signal. It may be variably set according to (output duty value from the F terminal).

In FIG. 9, as described above, the electric load correction value DB of the ISC valve opening is taken into the computer CNT through the engine speed and the output duty value from the F terminal (through the route shown in FIG. 1 above). FIG. 9 shows a two-dimensional map for variably determining the output duty value from the F terminal in accordance with the duty value of the pulse signal). And 25%, the relationship between the engine speed and the correction value DB (%) is shown by four curves (this curve corresponds to the torque value applied to the engine).

By reading the power generation duty (output duty value from the F terminal) of the alternator in this way, the load characteristic due to the power generation of the alternator at that time can be known, and the load characteristic due to the engine speed can be known. Is a map value corresponding to the torque applied to the engine, so that the electrical load on the alternator (and thus the I
The SC valve opening correction amount) can be calculated.

Therefore, by performing variable control based on such a map, the ISC valve opening correction amount based on the electric load and the basic I value when no load is applied.
It is possible to completely separate the correction amount of the SC valve opening, accurately predict the correction amount of the ISC valve opening based on the electric load, and surely perform the opening correction commensurate with the electric load at that time. You can Thus the basic I in the unloaded condition
Since it is possible to perform feedback control so that the SC valve opening can be maintained at a constant value, it is possible to further improve the engine speed stability and engine stalling resistance when the electric load is turned on or off. Also, there is no need to consider increasing the electrical load as an option.

[0024]

According to the present invention, even when an electric load such as a vehicle light is turned on or off during idle operation of the engine, fluctuations in the engine speed are reliably prevented, and engine stalling resistance is improved. And fuel efficiency can be improved.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of an idle speed control device as one embodiment of the present invention.

FIG. 2 is a timing diagram illustrating the operation of the device shown in FIG.

FIG. 3 is a flowchart illustrating a processing procedure for determining an electric load correction value DB of the ISC valve opening shown in FIG. 7.

FIG. 4 is a flowchart illustrating a processing procedure for determining an output to the field coil shown in FIG. 1.

FIG. 5 is a flowchart illustrating a processing procedure for determining the opening of the ISC valve shown in FIG.

FIG. 6 is a diagram illustrating a processing procedure for determining the opening degree of the ISC valve shown in FIG. 1 by a flowchart.

FIG. 7 is a diagram illustrating a processing procedure for determining the opening degree of the ISC valve shown in FIG. 1 with a flowchart.

FIG. 8 is a flowchart illustrating a processing procedure for determining the opening degree of the ISC valve shown in FIG. 1.

9 is a diagram illustrating a map for determining an electric load correction value DB of the ISC valve opening shown in FIG.

[Explanation of symbols]

 ALT ... Alternator FC ... Alternator field coil RG ... Regulator section B ... Vehicle battery L ... Load CNT ... Engine control computer

Claims (2)

[Claims] 1. A means for outputting a power generation request signal to an alternator according to an electric load connected to an alternator driven by an engine together with a vehicle battery.
Means for controlling the opening of the idle speed control valve when the output power generation request signal changes by a predetermined value or more, and means for setting a predetermined delay time from the time when the opening of the idle speed control valve is controlled And a means for supplying the field coil of the alternator with a field current having a value corrected according to the power generation request signal after the time set by the delay time setting means has elapsed. Number control device. 2. The opening degree of the idle speed control valve is variably controlled according to the engine speed and the value of the power generation request signal, whereby the opening degree is corrected in accordance with the electric load. The idle speed control device for an engine according to claim 1, wherein: