JPH0543867B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an idle rotation speed control device for an internal combustion engine.

<Prior art> As an idle rotation speed control device for an internal combustion engine,
For example, as shown in FIG. 4, an idle control valve (ISC valve) 3 is provided in the middle of the auxiliary air passage 2 that bypasses the throttle valve 7, and the idling rotation speed is controlled by adjusting the amount of auxiliary air. There is something I did. The idle control valve 3 is of a rotary type, and pulse signals are sent to a valve-opening coil and a valve-closing coil (not shown) in a mutually inverted state, and the opening degree is adjusted according to the duty ratio of the pulse signals. be adjusted.

Note that 9 is an SPI type fuel injection valve, 6 is a hot wire air flow meter, and 32 is a blow-by gas recirculation pipe.

The opening degree of the idle control valve 3 is controlled by a control unit (not shown) containing a built-in microcomputer that determines the operating state based on operating state detection signals such as engine rotational speed and engine cooling water temperature. This is done by changing the duty ratio (the proportion of time that the valve opening coil is ON) of the pulse signal as a control value supplied to the idle control valve 3 according to the state, and the engine rotation speed is adjusted to the target idle rotation speed. Feedback control is performed to ensure that

Further, there is a system which aims at further idling stability by controlling the ignition timing in parallel with the idling speed control by the idling control valve 3 (see Japanese Patent Application Laid-open No. 83665/1983).

This can be done, for example, by calculating the deviation between the target idle rotation speed and the engine rotation speed, searching for an ignition timing control value (ignition timing advance or retard correction amount) that is set in advance according to this deviation, and then The ignition timing is corrected and controlled based on the value, and when the engine speed is higher than the target idle speed, the ignition timing is retarded, and when it is lower than the target idle speed, the ignition timing is advanced. In this way, the synergistic effect with the auxiliary air flow rate control by the idle control valve 3 allows the engine rotation speed to be brought as close to the target idle rotation speed as possible and stably.

<Problems to be Solved by the Invention> However, the control of the auxiliary air flow rate and the ignition timing control by the idle control valve as described above are performed in parallel regardless of the deviation between the engine rotation speed and the target idle rotation speed. The following problems arose.

That is, as shown in FIG. 5, when the engine speed is high and the deviation from the target idle speed is large when returning to idle (in the figure, at the end of the dumppot control of the idle control valve 3), the auxiliary air flow rate control by the idle control valve 3 is performed. If ignition timing control is performed in parallel with
In order to eliminate a large deviation, sudden control (reduction of duty ratio and retardation of ignition timing) is performed, and there is a risk that undershoot may occur and hunting may be induced by this undershoot. Ta.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide an idle rotation speed control device that can suppress rapid rotation reduction during idle rotation speed control and perform stable control.

<Means for Solving the Problems> Therefore, in the present invention, as shown in FIG. An idle control means D that controls the opening degree of the idle control valve 3 that controls the air flow rate so that the engine rotation speed approaches a target idle rotation speed that has been set in advance according to the engine operation state in a predetermined idle operation state; a basic ignition timing setting means B that establishes a basic ignition timing based on the state; An ignition timing correction means E that corrects the basic ignition timing according to the deviation from the engine rotation speed, and an ignition timing control device C that controls ignition based on the set basic ignition timing or the corrected ignition timing. This constitutes an idle rotation speed control device for the internal combustion engine 1.

<Operation> According to this configuration, in a predetermined idle operating state in which idle rotation speed control is performed by the idle control valve, when there is a large deviation between the engine rotation speed and the target idle rotation speed, that is, in the predetermined rotation speed range in which ignition timing control is performed. When it is not within the range, it is avoided that the auxiliary air flow rate control and the ignition timing control are performed in parallel by the idle control valve, and the idle rotation speed is controlled only by controlling the auxiliary air flow rate.

Then, parallel control is performed when the engine rotation speed is within a predetermined rotation speed range including the target idle rotation speed and the deviation is small.

<Example> An example of the present invention will be described below based on the drawings.

In Figure 2, engine 1 includes air cleaner 2.
6. Air is taken in through the intake duct 31, the throttle chamber 4, and the intake manifold 5.

An air flow meter 6 is provided in the intake duct 31 and outputs a voltage signal corresponding to the intake air flow rate Q. The throttle chamber 4 includes a throttle valve 7 that is linked to an accelerator pedal (not shown).
is provided to control the intake air flow rate Q.
An idle control valve (ISC valve) 3 whose opening degree is adjusted according to the duty ratio of a pulse signal sent from a control unit 30 is provided in the middle of the auxiliary air passage 2 that bypasses the throttle valve 7. to control the auxiliary air flow rate.
The throttle valve 7 is attached with a midle switch 8 for detecting its fully closed position. The intake manifold 5 is provided with a fuel injection valve 9 for each cylinder whose opening is controlled by a control unit 30.

Each cylinder of the engine 1 is provided with an ignition plug 10, and a high voltage generated by an ignition coil 11 is sequentially applied to these via a distributor 12, thereby igniting a spark and mixing. Ignite and burn qi. The ignition coil 11 is controlled through a power transistor 13 attached thereto to control the timing at which high voltage is generated. Therefore, the ignition timing is controlled by controlling the ON/OFF timing of the power transistor 13 using an ignition timing control signal from the control unit 30.

Here, the ignition plug 10, the ignition coil 11, the distributor 12, and the control unit 30
The ignition timing control device is composed of the following.

The distributor 12 has a built-in photoelectric crank angle sensor 14. The photoelectric crank angle sensor 14 is connected to the distributor shaft 1.
Signal disk plate 1 that rotates together with 5
6 and a detection section 17. The signal disk plate 16 has 360 position signals (1°
A slit 18 for the signal) and four slits 19 for the reference signal (180° signal) in the case of a four-cylinder engine are formed, and one of the four reference signal slits is also used to identify the No. 1 cylinder. be. The detection section 17 detects these slits 18 and 19 and outputs a reference signal including a position signal and a cylinder discrimination signal. Here, by measuring the period of the reference signal, the engine rotational speed N
It is possible to calculate

In addition, a water temperature sensor 21 is provided that faces the water jacket 20 of the engine 1 and outputs a voltage signal corresponding to the engine cooling water temperature (hereinafter referred to as water temperature).

Furthermore, the control unit 30 controls ON/OFF of the neutral switch 24 and air conditioner switch 23 attached to the transmission 25.
A voltage signal corresponding to the vehicle speed from the vehicle speed sensor 22 is inputted.

As described above, the engine operating state detection means in this embodiment include the air flow meter 6, the idle switch 8, the photoelectric crank angle sensor 14, the water temperature sensor 21, the vehicle speed sensor 22, and the air conditioner switch 23.
and a neutral switch 24.

Here, the control unit 30
The flowchart shown in Fig. 3 (idle control valve 3
Input/output operations, arithmetic processing, etc. are performed according to a program based on a routine for calculating a control value ISCdy of a duty ratio of a pulse signal and a routine for setting an ignition timing control value. That is,
The control unit 30 serves as idle control means, basic ignition timing setting means, and ignition timing correction means.

Next, the flowchart shown in FIG. 3 will be explained.

In addition, S1 to S12 control the idle control valve 3,
S13 to S20 indicate ignition timing control.

In S1, a basic control value ISCtw is set from the water temperature Tw detected by the water temperature sensor 21. still,
This setting is made in advance in the control unit 30.
Basic control value with water temperature Tw as a parameter in ROM
This may be done by storing an ISCtw map and searching from that map, or it may be done by calculation.

In S2, the air conditioner and gear position correction amount ISCat is set from the ON/OFF signals of the neutral switch 24 and the air conditioner switch 23. this
ISCat is designed to increase the amount of correction when the load is large, such as when using an air conditioner or when the automatic transmission is in the D range.

In S3, the acceleration/deceleration correction amount ISCtr is set based on the vehicle speed signal from the vehicle speed sensor 22, the ON/OFF signal of the idle switch 8, etc. This ISCtr is set to prevent the negative pressure in the intake manifold 5 from increasing during deceleration, and to prevent engine stalling when the clutch is engaged when starting.

In S4, it is determined whether the ISC condition (area where ISC is performed) is met. Specifically, the idle switch 8, which detects the fully closed state of the throttle valve 7, is turned on.
(Throttle valve 7 is fully closed or close to fully closed)
When the big neutral switch 24 is ON,
Alternatively, when the idle switch 8 is ON and the vehicle speed detected by the vehicle speed sensor 22 is below a predetermined value, the ISC condition is established (YES), and S5
Set the flag to 1 and proceed to the next step, S7.

If it is determined in S4 that the ISC condition is not met (NO), the flag is set to 0 in S6 and the process jumps to S11.

In S7, the target rotational speed Ns is set by searching or calculating from the water temperature Tw detected by the water temperature sensor 21.

In S8, the target rotation speed Ns and the actual rotation speed N are compared, and ISCfd is set by integral control. In other words, if Ns>N, S9 uses integral control to
Increase ISCfd by a predetermined amount from the previous value, Ns<N
In this case, ISCfd is decreased by a predetermined amount from the previous value based on integral control in S10. Also, in S8, if Ns=N (including dead zone), ISCfd
remains at its previous value.

In S11, the control value ISCdy is calculated using the following equation.

ISCdy=ISCtw+ISCat+ISCtr+ISCfd The duty ratio based on this calculation result is output to the idle control valve 3 at SI2.

The above S1 to S12 correspond to idle control means.

In S13, the engine speed N and intake air flow rate Q are read as signals for searching the basic ignition timing, and the map value of the basic ignition timing (ADV) set and stored according to these values is used as the basic ignition timing. Search and obtain S14 as a setting means.

In S15, the flag is determined to determine whether the current operating state satisfies the ISC condition, that is, the determination result in S4 is re-examined to determine whether the operating state is one in which idle rotational speed control based on ignition timing is performed. If the flag is 1, it means that the ISC condition is satisfied, so the engine rotation speed, which is the second condition, is determined in the next step S16. If the flag = 0, the ISC condition is not satisfied, so S20
ignition processing based on the basic ignition timing.

In S16, a rotation speed (Ns+α) near the target rotation speed Ns, which is obtained by adding a predetermined rotation speed α (for example, about 0 to 50 rpm) to the target idle rotation speed Ns, is compared with the engine rotation speed N, and it is determined that Ns+α≧N. If the ignition timing is corrected in S17 to S19, Ns
If +α<N, flag = 0 in S15
Ignition processing is performed based on the basic ignition timing in the same way as in the case where it is determined that

In S17, a deviation ΔN between the target idle rotation speed Ns and the engine rotation speed N is calculated, and based on this ΔN, a correction value for the ignition timing is searched in S18. That is, a map value of the ignition timing correction value using .DELTA.N as a parameter is stored in advance in the ROM in the control unit 30, and this map value is searched using .DELTA.N calculated in S17.

In S19, the basic ignition timing obtained by searching in S14 is corrected using the ignition timing correction value searched in S18. That is, S15 to S19 correspond to the ignition timing correction means. Then, ignition processing is performed in S20 based on this corrected ignition timing.

With such a configuration, for example, when the engine rotation speed is higher than the target idle rotation speed at idle return and Ns+α<N, the engine rotation speed can be increased only by controlling the auxiliary air flow rate by the idle control valve 3. Since control is performed to approach the target idle rotation speed, even if there is a large deviation between the engine rotation speed and the target idle rotation speed, sudden control will not be performed and the engine rotation speed will gradually decrease and a large rotation will be achieved. can prevent the decline of
Hunting can be prevented from occurring.

Also, the engine rotation speed N is the target idle rotation speed
When the rotational speed becomes lower than Ns+α near Ns (Ns+α≧N), the idle control valve 3 performs control of the correction air flow rate and advance/retard control of the ignition timing in parallel. The target idle rotation speed can be controlled as much as possible, and the stability of the engine rotation speed N during idle is improved.

<Effects of the Invention> As explained above, according to the present invention, in the idle rotation speed control device that performs feedback control of the idle rotation speed by controlling the amount of auxiliary air, the actual rotation speed is lower than near the target idle rotation speed. Sometimes, the ignition timing is corrected depending on the deviation from the target rotational speed.

As a result, even if the engine rotation speed greatly exceeds the target idle rotation speed when returning to idle, etc., it is possible to prevent a sudden decrease in rotation due to feedback control and prevent hunting. When the actual engine speed is low, by controlling the amount of auxiliary air and correcting the ignition timing in parallel, it is possible to eliminate the drop in engine speed due to load application, etc. as soon as possible, and the engine speed during idling. It has the effect of stabilizing the

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing the configuration of the present invention, Fig. 2 is a schematic diagram showing an embodiment of the invention, Fig. 3 is a flowchart showing the control flow in the above, and Fig. 4 is a diagram of the idle control valve. FIG. 5 is a sectional view of a throttle chamber showing an example, and a time chart showing conventional control characteristics. 1...Internal combustion engine, 2...Auxiliary air passage, 3...
Idle control valve, 6... Air flow meter, 7...
...Throttle valve, 8...Idle switch, 10
... Spark plug, 11 ... Ignition coil, 12 ... Distributor, 14 ... Photoelectric crank angle sensor, 21 ... Water temperature sensor, 22 ... Vehicle speed sensor,
23... Air conditioner switch, 24... Neutral switch, 30... Control unit.

Claims (1)

[Claims] 1. Engine operating state detection means for detecting the operating state of the engine; and an engine operating state detecting means that detects the opening degree of an idle control valve that controls the air flow rate of an auxiliary air passage that bypasses the throttle valve in advance in a predetermined idle operating state of the engine. an idle control means for controlling the engine rotation speed to approach a target idle rotation speed set according to the engine operating state; a basic ignition timing setting means for setting the basic ignition timing based on the engine operating state; and the predetermined idle operating state. ignition timing correction means for correcting the basic ignition timing according to the deviation between the target idle rotation speed and the actual engine rotation speed only when the actual engine rotation speed is lower than near the target idle rotation speed; An ignition timing control device for controlling ignition based on the corrected basic ignition timing or corrected ignition timing; and an ignition timing control device for an internal combustion engine.