JPH0245638A - Idle speed control device for vehicle internal combustion engines - Google Patents

Abstract

PURPOSE:To suppress the excessive increase and reduction of the revolution speed by controlling an idle control valve on the basis of the difference between the aimed revolution speed and the actual revolution speed immediately after the opening, according to the actual variation of the revolution speed immediately after the turning-ON of an electrical load. CONSTITUTION:Immediately after an air conditioner switch is turned ON, the correction value ISCACF for air conditioner is searched from a map on the basis of the actual revolution speed change DELTAN in the process S7, and the control value ISCdy is set so that the actual variation DELTAN of revolution speed becomes the aimed revolution speed change. Immediately after turning-OFF an air conditioner switch, the revolution speed difference DELTAN between the detected actual revolution speed and the aimed idle revolution speed is calculated in the process S4, and the control value ISCdy is converged to the value which is set only by the engine operation state. Therefore, the generation of the engine stall can be prevented by suppressing the excessive increase and reduction of the revolution speed.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an idle speed control device for a vehicle internal combustion engine, and more particularly to a technique for improving idle speed control characteristics when an electric load is turned on and off.

<Prior art> As a conventional example of an idle speed control device, an idle control valve is installed in an auxiliary air passage that bypasses a throttle valve, and the opening degree of this idle control valve is controlled to adjust the idle speed to the target idle speed. There is a device in which feedback control is performed so that the number of points increases (see Japanese Patent Laid-Open No. 58-57623).

By the way, in a vehicle internal combustion engine, when an electrical load such as a near conditioner mounted on the vehicle is applied as an engine load, the idle speed decreases, which may cause engine stall.

For this reason, conventionally, idle rotation speed control is performed as follows.

That is, when the near conditioner is opened, that is, when the air conditioner switch is turned off, the idle rotation speed is adjusted by driving the idle control valve and controlling the air flow rate of the auxiliary air passage based on the control value I SC, obtained by the following equation. feedback control to achieve the target idle speed.

l5Cdy Engineering I S set, + I SC, L+ I
S Crb Here, rsc, , is a basic control value determined by the cooling water temperature, ISC,t is various correction values such as acceleration/deceleration correction, and l5Cfb is a feedback correction value.

Further, when the near conditioner is turned on (turning on the near conditioner), the following air conditioner control value l5CAc is added to the control value l5Cdy to increase the idle rotation speed by a predetermined value.

[S C5c= I S CAc5 + I S CA
cr Here, [S Cacs is a constant air conditioner basic control value, l5CAcF is the air conditioner basic control value l5
CAcs is a fixed air conditioner correction value that is added when the idle speed does not rise sufficiently.

<Problem to be Solved by the Invention> However, in such a conventional idle speed control device, when the air conditioner switch is turned on, the control value rsc, . Since the correction value ■5CAc is added for
There were the following problems.

That is, if the same air conditioner correction value l5CAc is used in the same model engine or idle control valve,
Due to manufacturing variations in engines or idle control valves, when the air conditioner is turned on, the idle speed of the engine may increase or decrease excessively, as shown by the chain line in FIG.

This has resulted in problems such as causing discomfort due to an excessive increase in rotation, and causing engine stall due to a decrease in rotation.

Conversely, when the air conditioner switch is turned off (near conditioner open), the air conditioner correction value 15CAC is suddenly no longer added to the control value ISC, ., so the idle speed drops rapidly. This caused a problem in that the idle speed decreased excessively, leading to the occurrence of engine stall.

The present invention was made in view of the above-mentioned circumstances, and by suppressing rotational speed fluctuations when an electrical load is turned on and when the electrical load is released, an excessive increase in the rotational speed and an excessive increase in the rotational speed can be prevented. It is an object of the present invention to provide an idle rotation speed control device that can suppress a decrease.

<Means for Solving the Problems> For this reason, the present invention, as shown in FIG. A control value setting means B for setting a control value so that the idle rotation speed becomes a target idle rotation speed, and an electric load control device for setting an electric load control device to increase the target rotation speed by a predetermined value when the electric load is turned on. A control value setting means C, and a drive control means for driving and controlling the idle control valve A by adding the electric load control value to the control device while the electric load is turned on, wherein the actual idle rotation a rotation speed detection means E for detecting the number of rotations; a first correction means F for correcting the electrical load control value; and immediately after releasing the electrical load, based on the rotational speed difference between the target idle rotational speed at the time of electrical load release and the detected actual rotational speed, a reduction value setting means G that sets a reduction value so that the rotation speed difference becomes smaller as the rotation speed difference becomes smaller; and a reduction value setting means G that corrects the electric load control value based on the set reduction value and adds the control value. 2 correction means H.

Immediately after the electric load is turned on, the idle control valve is driven and controlled so that the actual rotation speed change becomes the target rotation speed change, thereby suppressing an excessive rotation upper limit. Immediately after the electrical load is released, the idle control valve is driven and controlled based on the difference between the target idle rotation speed and the actual rotation speed, thereby suppressing an excessive decrease in rotation speed.

<Example> An example of the present invention will be described below with reference to FIGS. 2 and 3.

In FIG. 2, the engine 1 includes an air cleaner 2°, an intake duct 3. Throttle chamber 4 and intake manifold 5
Air is inhaled through.

An air flow meter 6 is provided in the intake duct 3 and outputs a voltage signal corresponding to the intake air flow rate. The throttle chamber 4 is provided with a throttle valve 7 that operates in conjunction with an accelerator pedal (not shown) to control the intake air flow rate. An idle switch 8 is attached to the throttle valve 7 to detect its fully closed position. Also, throttle valve 7
An auxiliary air passage 9 is provided to bypass the auxiliary air passage 9, and an idle control valve 10 is interposed in this auxiliary air passage 9.

The opening degree of this idle control valve 10 is controlled by a signal from a control device 11, which will be described later.

The intake manifold 5 is provided with a fuel injection valve 12 for each cylinder, which is opened in response to a drive pulse signal from the control device 11 and injects fuel that is pressure-fed from a fuel pump (not shown) and controlled to a predetermined pressure by a pressure regulator. Injection is supplied to engine 1.

Each cylinder of the engine 1 is provided with an ignition plug 13, to which a high voltage generated by an ignition coil 14 is sequentially applied via a distributor 15, thereby igniting a spark to ignite and burn the air-fuel mixture. Here, the ignition coil 14
The generation timing of the high voltage is controlled via the power transistor 16 attached thereto. Therefore, the ignition timing is controlled by controlling the ON/OFF timing of the power transistor 16 using an ignition signal from the control device 11, which will be described later.

A photoelectric crank angle sensor 1 is installed in the distributor 15.
7 is built-in. The photoelectric crank angle sensor 17 is
It consists of a signal disc plate 9 that rotates together with the distributor shaft 18 and a detection section 20. The signal plate 19 has 360 position signals (
1° signal) slit 21, and in the case of 4 cylinders, 4 reference signal (180° signal) slits 22 are formed;
One of them is also used to identify the #1 cylinder. The detection unit 20 detects these slits 21, 22 and generates position signals (36 per revolution of the distributor shaft 18).
720 position signals from 0 slits 21) and a reference signal including a #1 cylinder discrimination signal. Therefore, the crank angle sensor 17 constitutes a means for detecting the engine speed. Further, an on/off signal from an air conditioner switch (not shown) is input to the control value Wll.

Here, the control device If operates according to a program based on the flowchart shown in FIG.

Here, the control value W11 constitutes the control value setting means, the electrical load control value setting means, the first and second correction means, and the reduction value setting means.

Next, the operation will be explained according to the flowchart shown in FIG.

This routine is activated when the idle switch 8 is turned on.

Sl reads various signals such as the rotational speed signal from the crank angle sensor 17 and the on/off signal of the air conditioner switch.

In S2, select whether the air conditioner switch turned from off to on, from on to off, or whether it remains off. When it changes from off to on, proceed to S3 and change from on to off. If the off state continues, the process advances to S5.

In S3, a constant air conditioner basic control value ISCAc5 is added to the control value ISC set based on the engine operating state, as in the conventional example, and the idle control valve 10 is driven and controlled based on this value. Proceed to S6.

This causes the idle speed to begin to rise.

In S6, the rotation speed change ΔN per unit time during rising is calculated based on the detected idle rotation speed. Specifically, from the current rotation speed to before the reference signal or 10. ,
, subtract the previous rotation speed to obtain the rotation speed change ΔN per unit time.
Calculate.

In S7, the air conditioner correction value I S CACF is searched from the map based on the calculated actual rotational speed change ΔN. This air conditioner correction value l5CACF is the rotation speed change Δ
It is set to become smaller as N becomes larger.

In S8, after calculating the air conditioner control value l5CAC by adding the searched air conditioner correction value l5CACF and the air conditioner basic control value l5CAcs, the control value ISC,
, is calculated using the following formula.

I S Cd, = l S CL, + [S C,t+
If you do something like I S Ctb+ I S CA,
The air conditioner correction value l5CACF is set to decrease as the rotational speed change ΔN increases.
The air conditioner control value l5CAC is corrected to become smaller as the rotational speed change ΔN becomes larger. As a result, immediately after the air conditioner switch is turned on, the control value ISC is set so that the actual rotational speed change ΔN becomes the target rotational speed change, so that it is possible to suppress the rotational speed from increasing excessively.

On the other hand, in S4, after calculating the rotational speed difference ΔN between the detected actual rotational speed and the target idle rotational speed (value when the near conditioner is off), the process proceeds to S9.

In S9, a reduction value DAC is searched from the map based on the rotational speed difference ΔN. This reduction value DAC is set to increase as the rotational speed difference ΔN increases.

In the SIO, the control value ISC, , is calculated using the following equation.

I SCd,"' I SCt, + I 5C-t+
If I 5Ctb + I SCA, -DA, the reduction value DAC is set to increase as the rotational speed difference ΔN increases, so the control value l5Cov will drop rapidly at the beginning of the addition of the reduction value DAC. Then, when the rotation speed ΔN becomes smaller, the control value l5Cd
y gradually decreases and converges to the control value ISC,y, which is set only based on the engine operating state. For this reason, the rotational speed also decreases rapidly and then gradually converges to the target rotational speed, so that an excessive decrease in the rotational speed can be suppressed, and the occurrence of enrichment can be prevented.

In S5, a control value l5Cdy is calculated based on the engine operating state.

The idle control valve 10 is driven and controlled based on the control values 13c and y thus obtained.

<Effects of the Invention> As explained above, the present invention corrects the electrical load control value and adds it to the control value so that the actual rotational speed change becomes the target rotational speed change immediately after the electric load is turned on. In addition, immediately after the electrical load is released, a reduction value is set based on the difference in rotational speed between the actual rotational speed and the target idle rotational speed, and after correcting the electrical load control value, it is added to the control value. It is possible to suppress an excessive increase in the rotational speed, and also to suppress an excessive decrease in the rotational speed to prevent the occurrence of engine stall, thereby improving idle rotational speed control.

[Brief explanation of the drawing]

Fig. 1 is a claim correspondence diagram of the present invention, Fig. 2 is a configuration diagram showing an embodiment of the present invention, Fig. 3 is a flowchart of the same as above,
FIG. 4 is a diagram for explaining the drawbacks of the conventional example. 7...Throttle valve...Idle control valve angle sensor 9...Auxiliary air passage 10 11...Control device 17...Kura patent applicant Japan Electronics Co., Ltd. Agent Patent attorney Tomiji Sasashima Male Fig. 2 Fig. 4 Fig. 1”IN

Claims (1)

[Claims] an idle control valve that controls the air flow rate of an auxiliary air passage that bypasses the throttle valve; a control value setting means that sets a control value so that the idle speed becomes the target idle speed based on the engine operating state; and an electric load. an electric load control value setting means for setting an electric load control value so as to increase the target rotation speed by a predetermined value when the electric load is turned on; An idle rotation speed control device for a vehicle internal combustion engine, comprising: a drive control means for driving and controlling an idle control valve;
A rotation speed detection means for detecting an actual idle rotation speed, and immediately after the electric load is turned on, the actual rotation speed change per unit time becomes the target rotation speed change per unit time based on the detected actual rotation speed. a first correction means for correcting the electrical load control value so that the electric load control value is corrected; a reduction value setting means for setting a reduction value so that the rotation speed difference becomes smaller as the rotation speed difference becomes smaller; and a reduction value setting means for correcting the electric load control value based on the set reduction value and adding it to the control value. An idle rotation speed control device for a vehicle internal combustion engine, comprising: a second correction means.