JPH02136540A - Internal combustion engine idle speed control device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a technique for improving the control performance of the idle speed after startup in a device for controlling the idle speed of an internal combustion engine.

<Prior art> In an internal combustion engine equipped with an electronic side '<8 fuel injection device, the opening degree of an electromagnetic idle control valve installed in a passage bypassing an intake throttle valve is controlled by duty. Controls idle speed.

During cranking, the idle control valve is maintained at a constant opening control amount set by water temperature, etc., but after cranking, that is, after starting, conventionally feedback control is performed to bring the idle rotation speed closer to the target rotation speed. It is common to do so.

<Problems to be Solved by the Invention> By the way, in the feedback control described above, the opening control amount is usually set by proportional integral control, but it is also possible to set the opening control amount by proportional-integral control, but it is also possible to set the opening control amount by proportional-integral control. When controlling using a large-flow idle control valve such as the one included, in order to ensure responsiveness, the proportional bone l5CFBF given when the magnitude relationship between the actual rotation speed and the target rotation speed is reversed is set to the target rotation. The following formula is used depending on the deviation ΔN between the number of rotations and the actual number of rotations.

I S CFIP = (ΔN/N,)” ・K0 However, No is the standard deviation rotation speed, for example 50 rpm,
Ko is a constant set including calculations by a microcomputer.

However, in this way, the proportional bone is set to 2 for the deviation ΔN.
In a control method that increases the number of revolutions in succession, if the starter switch is turned OFF to end cranking before the cranking revolutions have risen sufficiently, especially at low temperatures, the actual revolutions will decrease when feedback control is subsequently started. Since the number of rotations is significantly lower than the target rotation speed, the proportional bone l5CPIF set by the above formula becomes a considerably large value, and as shown in Fig. 5, the rotation speed increases and hunting occurs. This has caused a problem in that the feeling has worsened.

The present invention was made in view of these conventional problems, and an object of the present invention is to provide an idle speed control device for an internal combustion engine that can smoothly start up the idle speed after cranking. do.

<Means for Solving the Problems> Therefore, as shown in FIG. 1, the present invention controls the idle rotation speed by controlling the opening degree of an idle control valve installed in a passage that bypasses the intake throttle valve. and the opening side '4i of the idle control valve so as to bring the engine speed close to the target speed at least under predetermined idle operating conditions.
An idle rotation speed control device for an internal combustion engine, which includes a feedback control means that performs proportional-integral control over 1 fit, includes a cranking detection means that detects cranking, and a crank that sets an opening control amount of an idle control valve during cranking. A ranking opening control amount setting means, a timing means for measuring the elapsed time after the end of cranking, and the feedback control means are configured to stop adding proportional bone for a predetermined period of time after the end of cranking and control the opening only by integral control. control switching means for controlling the amount of opening and, after the predetermined time has elapsed, for controlling the opening control amount using proportional-integral control as usual.

Function> During cranking detected by the cranking detection means, the cranking opening control amount setting means maintains the idle control valve at a constant opening control amount set by the water temperature or the like.

When cranking is finished, for a predetermined period of time measured by the timer after the cranking is finished, the control switching means
The feedback control means controls the opening control amount of the idle control valve only by integral control without adding a proportional bone. Immediately after cranking, the deviation between the target rotational speed and the actual rotational speed is usually quite large, but since the proportional bone is not added, a sudden increase in the rotational speed can be suppressed, and the integral control smoothly approaches the target rotational speed.After the predetermined time elapses, In this case, the feedback control means normally controls the opening control amount of the idle control valve by proportional-integral control using the control switching means.

As a result, feedback control of the idle rotation speed is performed with a good balance between responsiveness and stability.

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

In FIG. 2 showing the configuration of one embodiment, an idle control valve 5 is interposed in an auxiliary air passage 4 that bypass-connects the upstream and downstream sides of an intake throttle valve 3 installed in an intake passage 2 of an engine 1. The idle speed is controlled by controlling the opening degree of the idle control valve 5 according to the operating state of the engine.

The opening control amount of the idle control valve 5 is detected by a signal from an idle switch 6 which is ON when the intake throttle valve 3 is in the idle position and OFF otherwise, a cooling water temperature detected by a water temperature sensor 7, and a crank angle sensor 8. engine speed, ON/OFF from start switch 9
The control unit 10 determines the engine operating state based on signals etc., and adjusts the idle control valve 5 according to the operating state.
Valve opening duty of the pulse signal supplied to
This is done as described below by changing .

In addition, on the upstream side of the intake throttle valve 3 in the intake passage 2,
An air flow meter 11 is provided to detect the intake air flow rate, and an air cleaner 12 is further provided upstream of the air flow meter 11.

Idle rotation speed control by the control unit OL will be explained below with reference to the flowchart of FIG. 3.

In step (denoted as S in the figure) 1, it is determined whether or not cranking is in progress by determining whether the start switch 9 is ON or OFF. That is, the start switch 9 and the function of step 1 constitute cranking detection means.

When it is determined that the start switch 9 is ON in step 1, that is, cranking is in progress, the process proceeds to step 2, and the idle control valve 5 is opened during cranking based on the cooling water temperature detected by the water temperature sensor 7. Duty ISC
is searched or calculated from the map stored in R'OM and set to l5C3T. That is, the function of this step corresponds to cranking opening control amount setting means. Next, the routine proceeds to step 3, where the timer T, which is used to measure the elapsed time after the cranking is completed, is reset to 0, and this routine ends.

On the other hand, when it is determined in step 1 that the start switch 9 is OFF, the process proceeds to step 4 and the water temperature T is determined in order to start feedback control to bring the idle rotation speed closer to the target rotation speed. etc., the target rotation speed NA is set by searching from a map, etc.

Next, proceed to step 5 and set the water temperature T. Proportional bone addition cancellation time T according to. Search from the map.

Further, the process proceeds to step 6 where the timer is counted up, and then the process proceeds to step 7, where the magnitude relationship between the set target rotational speed NA and the engine rotational speed N detected by the crank angle sensor 8 is compared.

Then, when it is determined that N a > N, step 8
Then, from the count value of the timer, it is determined whether the elapsed time T after the end of cranking has reached the additional cancellation time T0, and when it is determined that T0 has not yet elapsed,
Proceed to step 9 without adding the proportional bone, and add the integral IS to the current opening duty ISO of the idle control valve 5.
The value added with CFBI is updated and set as a new ISO. Here, the basic value of the ISC immediately after cranking is set based on the water temperature, and feedback control is started with this value as the initial value. Large flow idle control valve 5
In this case, especially at low temperatures, the basic value is the opening control amount ISO! during cranking. It is not much different in size from I7.

Further, when it is determined in step 8 that To has elapsed, the process proceeds to step 10, and it is determined whether or not it has just become NA>N (the previous determination was NA≦N).

When it is determined that the situation has just become NA>N, the process proceeds to step 11, and the value obtained by adding the proportional bone I SC,, P is updated and set as a new ISO, and from the second time onward, the process proceeds to step 9 to integrate. The value obtained by adding minutes ISCFg+ is updated and set as a new ISC.

Here, the proportional bone l5CFIP is calculated using the above-mentioned calculation formula (I
5CFBP = (ΔN/N,)"・Ko), and immediately after cranking, especially at low temperatures, the deviation ΔN is large, so it is set to a large value. On the other hand, l5CFBI is determined by the deviation Δ
I5CFIIP>>I is set primarily for N.
It is related to S CFII+.

Furthermore, when it is determined in step 7 that NA
SC is updated with the value obtained by subtracting the integral l5CFBI from the current value, and after reaching To, in step 14 NA <
It is determined whether or not it is the first time of H. For the first time, the process proceeds to step 15 and the proportional bone l5CFBP is subtracted, and from the second time onwards, the value obtained by subtracting the integral I S CyBt is updated and set.

If it is determined in step 7 that NA=N, this routine ends.

In this way, after setting the valve opening duty ISC of the idle control valve 5 according to the operating state, a pulse signal with the set valve opening duty ISC is output to the idle control valve 5. is controlled to a predetermined opening degree.

In addition, in the above routine, steps 4 and 7°9 to 1
The functions of steps 1.13 to 15 constitute a feedback control means, and the functions of steps 5 and 8.12 constitute a control switching means.

If such control is performed, the opening of the idle control valve 5 is controlled by the opening control amount set only by integral control for a predetermined time after cranking is completed, without adding a proportional component that is set as a large value. As a result, the rotational speed increase after startup becomes smooth as shown in Figure 4, and it is possible to prevent the rotational speed from spiking or hunting, which is caused by the conventional feedback control that adds a proportional amount immediately after cranking at low temperatures. Improves starting feeling.

Further, after a predetermined period of time has elapsed and the engine speed approaches the target speed, proportional-integral control is performed as usual, and feedback control of the idle speed is performed to achieve a balance between responsiveness and stability.

<Effects of the Invention> As explained above, according to the present invention, particularly in controlling the idle rotation speed using a large flow rate idle control valve,
The effect is that the increase in engine speed after startup becomes smooth and the feeling is improved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of the present invention, and FIG. 2 is a block diagram showing the configuration of the present invention.
FIG. 3 is a flowchart showing the idle rotation speed control routine according to the embodiment of the present invention; FIG. 4 is a time chart showing the control state during control of the above embodiment; FIG. 1 is a time chart showing a control state during control in a conventional example. ■ Engine 2 Intake passage 3 Intake throttle valve 4 Auxiliary air passage Idle control valve 6 Idle switch 8 Crank angle sensor 9 Start switch 1o
...Control unit Fig. 4 Patent applicant Japan Electronics Co., Ltd. Agent Patent attorney Fujio Sasashima Sudarto 5WOFF Fig. 5 Start SW, OFF

Claims (1)

[Claims] The idle speed is controlled by controlling the opening degree of an idle control valve installed in a passage that bypasses the intake throttle valve, and the idle speed is controlled so that the engine speed approaches the target speed at least under predetermined idle operating conditions. An idle rotation speed control device for an internal combustion engine comprising a feedback control means for proportional integral control of an opening control amount of a control valve, a cranking detection means for detecting cranking, and an opening of the idle control valve during cranking. A cranking opening control amount setting means for setting a control amount, a clock means for measuring the elapsed time after the end of cranking, and an integral control method for controlling the feedback control means by stopping adding the proportional component for a predetermined time after the end of cranking. control switching means that operates to control the opening control amount only by the control alone, and after the predetermined time has elapsed, controls the opening control amount by proportional integral control as usual. Idle speed control device for internal combustion engines.