JPS63263233A - Electronic controller of engine - Google Patents

Abstract

PURPOSE:To increase the control precision and improve the stableness by setting a dead zone ranging over the specified zone when a control variable goes near a target value within the specified range and interrupting the feedback control when the control variable goes into the dead zone. CONSTITUTION:The signal from a crank angle sensor 31 is sent to a controller 30, which controls a throttle bypass valve 23 to have the idle running speed meet the target value. When the current running speed comes near the target value within the specified range, a new dead zone ranging over said range is set and the feedback control is interrupted when the current running speed is within the newly set dead zone when the current running speed comes out of said dead zone, the dead zone is reset to a narrower dead zone and the feedback control is recovered. The control precision is then increased and the control is made stable.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an electronically controlled tIlI device that controls control values such as engine idle speed and air-fuel ratio to target values.

(Prior Art) Conventionally, when controlling engine idle speed, air-fuel ratio, etc. by an electronic control device, feedback control has generally been performed so that these control values converge to a target value.

In addition, in the feedback control described above, a technique of setting a dead zone with a certain width with respect to the target value and stopping the feedback control when the control value falls within this dead zone is disclosed in, for example, Japanese Patent Laid-Open No. 55 It is publicly known as seen in No. 98628.

(Problem to be Solved by the Invention) However, when performing control by setting a dead zone as described above, if the width of the dead zone is narrow, the convergence speed to the target value is large and the convergence accuracy is high. , a hunting phenomenon occurs in control near the target value, causing a problem in control stability.

Furthermore, the fluctuation range of the control value differs due to individual engine errors, aging, etc., and even if feedback control is attempted to control these fluctuation ranges, it will instead result in unnecessary feedback control that impedes control stability, resulting in the above-mentioned problem. It is preferable not to perform feedback control for fluctuations due to individual engine errors, aging, etc. On the other hand, when the width of the dead zone is wide and the control value is stable near the upper and lower limits of the dead zone, there is a problem that the deviation from the target value becomes large and the convergence accuracy decreases.

Therefore, in view of the above circumstances, the present invention aims to provide an electronic control device for an engine that avoids unnecessary feedback control and improves the stability of the engine without increasing the deviation from the target value. That is.

(Means for solving the problem) Electronic control of the present invention! The ll@ arrangement includes a control value detection means for detecting a control value of the engine, a target value setting means for setting a control target value, and a control value detecting means for detecting a control value of the engine, a target value setting means for setting a control target value, and the above-mentioned A dead zone setting means for setting a dead zone having a width larger than a predetermined value, and a feedback control means for setting a feedback 1-control signal so that the control value matches a target value, and stopping feedback control when the control value falls within the dead zone. It is characterized by having the following.

FIG. 1 is an overall configuration diagram for clearly showing the configuration of the present invention.

An operating state control means 2 is provided for the engine 1 to control the operating state of the engine 1 by controlling, for example, its idle speed and air-fuel ratio. The operating state control means 2 is set with the amount 1iIIIIIIl. It outputs a control signal from the control tlDffi setting means 3 and controls the engine 1 to a predetermined operating state.

Further, a signal from the feedback control means 4 is outputted to the control amount setting means 3, and a control signal is set based on this signal. Cough feedback control means 4
control value detection means 5 for detecting the control value of the engine 1;
Then, signals are output from the target value setting means 6 for setting the control target value and the dead zone setting means 7 for setting the dead zone.

The dead zone setting means 7 sets a dead zone having a width larger than the predetermined value when the burial value approaches at least a predetermined value or less with respect to the target value, and for example, when the control value approaches the predetermined value or less. Either set a narrow dead zone that is equal to this predetermined value until the control value reaches the target value, and then set a wider dead zone that is larger than the predetermined value when it falls within this narrow dead zone, or set a wide dead zone only when the control value matches the target value. It is something.

Then, the feedback control means 4 sets a feedback control signal so that the control value detected by the control value detection means 5 matches the target value set by the target value setting means 6, and also sets the control value so that the control value is within the dead zone. Then, a signal for stopping the feedback control is output to the approximately 2 control Dffi setting means 3.

(Function) In the above-mentioned electronic control device, if the control value deviates greatly from the target value, a narrow dead zone is set or no dead zone is set, and the feedback control means adjusts the control value to match the target value. When the control value approaches the target value below a predetermined value, a wide dead zone is set and feedback control is stopped to improve the accuracy of convergence of the control value to the target value. At the same time, the engine stability is ensured without unnecessary feedback control.

(Example) The present invention will be described in detail below with reference to the drawings.

FIG. 2 is an overall configuration diagram of a specific example of an electronic control device for an engine, and this embodiment shows an example of control for idle speed control.

Intake passage 12 that supplies intake air to the combustion chamber 11 of the engine 1
An air cleaner 13, an air flow meter 14 for measuring the intake flow rate, a throttle valve 15, a surge tank 16, and an injector 17 are installed in this order from the upstream side. Also, an exhaust passage 18 that leads out exhaust gas from the combustion chamber 11
An air-fuel ratio sensor 19 (linear 02 sensor), a catalyst device 20 for purifying exhaust gas, and a silencer 21 are installed in the engine.

The intake passage 12 is provided with a bypass passage 2f122 that bypasses the throttle valve 15, and this bypass passage 22 has a bypass regulating valve 23 (SC valve) made of a duty solenoid pulp that controls the amount of bypass air.
is interposed. Further, fuel from a fuel tank 25 is pumped to the indicator I tank 17 by a fuel pump 26. Further, a discharge voltage from an ignition coil 28 is applied to a spark plug 27 facing the combustion chamber 11 of the engine 1 via a distributor 29 .

A regulating valve 23 interposed in the bypass passage 22
A control signal (duty signal) is output from the control unit 30, and the idle rotation speed is controlled by the bypass air adjustment.

In addition, the control unit 30 is also attached to the indicator I controller 17.
A control signal is output from the fuel injection valve to control the fuel injection amount.

In order to detect the operating state of the engine 1, the control unit 30 receives an intake air amount signal from the air flow meter 14 and an air-fuel ratio signal from the air-fuel ratio sensor 19, and also receives an input from the crank angle sensor 31 of the distributor 29. An engine rotation signal from the engine, a water temperature signal from a water temperature sensor 32 that detects the engine water temperature, and an external load signal from a load switch 33 such as an air conditioner switch are input.

The control unit 30 performs feedback control so that the idle rotation speed reaches a predetermined target value based on the signals from the various sensors described above, and in this idle rotation speed control, it controls the idle rotation speed according to the detected rotation speed and the magnitude of the target value. Two types of dead zones, large and small, can be selected and set. In other words, if the detected rotation speed deviates significantly from the target value, a narrow first dead zone is set, and when the detected rotation speed falls within this first dead zone, a wide second dead zone is set. It is something to do.

The processing of the control unit 30 will be explained based on the flowchart of FIG. This flowchart only shows the routine for idle rotation fraud control. After starting, initialization is performed in step S1, and engine water temperature, load conditions, etc. are read in step S2. Then, in step S3, it is determined whether the feedback condition is satisfied, for example, by determining whether 5 seconds have elapsed after starting.

7. If the feedback condition is satisfied in step S3 with YES, then in step S4 a target value of rotational speed Ne is set according to the engine water temperature, load conditions, etc., and in step S5, the actual engine rotational speed N is read. Then, in step S6, it is determined whether or not a flag F, which will be described later, is O. Since this flag F is reset to 0 in the initial state, if YES is determined, the process proceeds to step S7, and the dead band width Nf is changed to a narrow width N1. Set to the first dead zone.

In step S9, it is determined whether or not the engine speed N is within the range of the dead band Nf (first dead band) with respect to the target speed Ne. If the determination is No outside the range, step S10 is performed to perform feedback control. It is determined whether the engine rotation speed N is lower than the target rotation speed N8, and if YES, the engine rotation speed N is lower, a constant Ka is added to the feedback correction coefficient C15c in step 811, while if the engine rotation speed N is higher. If No, the correction coefficient Qisc is corrected by subtracting the constant IKb from the correction coefficient Qisc in step 812, and the 7 lag F is held at 0 in step 813. Then, in step 815, the W control amount Qisc is controlled by the correction coefficient C15c, and in step 816, the bypass regulating valve 23 is controlled to this control 5iQisc.

When the engine speed N falls within the range of the first dead zone N1 due to the feedback control as described above, and the determination in step S9 becomes YES, the 7 lag F is set to 1 in step 814, and steps 810 to 812 are performed. At the same time as stopping the feedback control, N in step S6
Based on the O determination, the dead zone @Nf is set to a second dead zone having a width N2 wider than the first dead zone in step S8.

The first dead zone Nl is set to be the minimum fluctuation range or less when considering engine variations, aging, etc., and the second dead zone N2 is set to the maximum fluctuation range or more. be.

After setting the second dead zone N2 as described above, if the engine speed N deviates outside the range of the second dead zone, step S9
Based on the NO determination, feedback control is performed in steps S10 to 812, and the flag F is reset to O in step 813. By resetting this flag, the determination in step S6 becomes YES, and the width Nf of the dead zone is set to the narrow first dead zone N1.

Fig. 4 shows a time chart of control in engine rotational fluctuations, A shows fluctuations in engine rotational speed N with respect to target rotational speed °Ne and dead zone settings, and B shows control @Qis.
As feedback control is started at point a, a narrow first dead zone N1 is set, and as a result of this feedback control, the engine speed N approaches the target rotation speed Ne, and at point b, the first dead zone N1 is set. When it enters the range of one dead zone N1, feedback control is stopped and switched to a second dead zone N2 having a wider width.

Also, at point 0, an external load such as an air conditioner switch is turned on and the engine speed N decreases, and when the engine speed N goes out of the second dead zone N2 at point d, feedback control is resumed and the narrow 1 Switch to dead zone N1. Then, when it enters the range of the first dead zone at point e, the feedback control is stopped and switched to the second dead zone N2 having a wider width. Furthermore, at point f, the external load is turned off and the engine speed N increases, and at point q, when the engine speed N goes out of the range of the second dead zone N2, feedback control is resumed and the narrow first dead zone N1 is reached. Similar control is performed to switch.

In the embodiment described above, when performing feedback control, a narrow dead zone is set to improve the accuracy of convergence to the target rotation speed, but when the target rotation speed is approached, the dead zone is changed to a wide dead zone, and after the feedback control is stopped, the engine Irrespective of the size of the periodic rotation V1 rib, which varies depending on the condition, the feedback is stabilized in the stopped state to avoid unnecessary feedback.

Note that in the above embodiment, the first dead zone is set in a narrow range during feedback control; however,
Feedback control may be performed without setting this first dead zone, and a wide dead zone corresponding to the second dead zone may be set only when the target rotational speed is crossed. In addition to idle speed control using bypass air control as described above, this light can be applied to various feedback controls such as air-fuel ratio feedback control based on a detection signal from an air-fuel ratio sensor (linear 02 sensor), etc. . 7 (Effects of the Invention) According to the present invention as described above, there is provided a dead zone setting means for setting a dead zone having a width larger than the predetermined value when the control value approaches at least a predetermined value or less with respect to the target value. , if the control value deviates greatly from the target value, a narrow dead zone is set or no dead zone is set; if the control value approaches the target value below a predetermined value, a wide dead zone is set and feedback control is stopped. This improves the accuracy of convergence of the control value to the target value without increasing the deviation of the control value from the target value, and prevents unnecessary feedback control for fluctuations caused by engine variations, aging, etc. This makes it possible to ensure the stability of the engine.

[Brief explanation of the drawing]

Figure 1 is a block diagram to clarify the configuration of the present invention, Figure 2 is an overall configuration diagram of a specific example, Figure 3 is a flowchart to explain the processing of the control unit, and Figure 4 is the idle rotation speed. It is a time chart figure in control. 1... Engine, 2... Operating state control means, 3... Control Dffi setting means, 4...
... Feedback control means, 5 ... Control value detection means, 6 ... Target value detection means, 7 ...
...Dead band setting means, 23...Adjustment valve, 30.
·····control unit.

Claims (1)

[Claims] (1) An electronic control device for an engine that controls the operating state of the engine so that a control value such as an idle speed becomes a predetermined value, which includes a control value detection means for detecting a control value of the engine, and a control target value. a target value setting means for setting a dead zone having a width larger than the predetermined value when the control value approaches at least a predetermined value or less with respect to the target value; 1. An electronic control device for an engine, comprising feedback control means for setting a feedback control signal so that the control value falls within a dead zone, and for stopping feedback control when a control value falls within a dead zone.