JPS59120750A - Device for controlling idling number of revolution - Google Patents

Abstract

PURPOSE:To obtain stabilized controlling characteristics by obtaining the initial value of the reference position of an actuator when starting a feedback control upon entering the idling engine speed control, from the average value of the actuator control position during the previous feedback controlling. CONSTITUTION:When the opening of the throttle valve 3 of a carburetor 1 is controlled by means of a negative-pressure actuator 5 through a lever 2 and a rod 6, and the negative pressure in the pilot chamber 14 of the negative-pressure actuator 5 is controlled by a solenoid valve 16 having an atmosphere-opening orifice 17, the solenoid valve 16 is controlled by a control circuit 25. This circuit 25 feedback controls the idling engine speed in accordance with the water temperature, and it has a means to detect and store the average value of control data on the solenoid valve 16 being feedback controlled. And, when starting the feedback control, its average value is used as the initial control data to carry out feedback control.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to the control of the rotation speed of an internal combustion engine in an idling state, and particularly to a control device suitable for controlling the idle rotation speed of an internal combustion engine for an automobile.

[Prior art]

Internal combustion engines such as gasoline engines, especially internal combustion engines for automobiles, are often operated alternately between an idling state and a power generation state, and the frequency of these operations is generally quite high. The control of the engine speed when the engine is in a state of operation has become important from the viewpoint of exhaust gas countermeasures and energy saving. Idle speed control devices that are designed to always maintain an optimum idle speed depending on the speed of the vehicle have come into wide use.

Although it is generally commonly referred to as the rotation speed, the rotation speed referred to above and below refers to the same rotation speed,
It goes without saying that the example is [rpm].

By the way, in order to control the idle speed of an internal combustion engine, a suitable actuator is used to control the amount of intake air when the engine enters the idle operating state so that the engine speed reaches a predetermined value. However, there are two methods for controlling the amount of intake air using the actuator in this case: A method is provided in which a passage bypasses the throttle valve, and the amount of intake air flowing through this passage is controlled by the actuator.
A method in which the return position opening degree of the throttle valve is controlled by an actuator is mainly used.

However, no matter which of these methods is adopted, when the engine and load are coupled, for example in a car, when the gear is in a position other than neutral and the clutch is not depressed, Alternatively, if the throttle valve is in a state where it is opened from the return position, for example when the accelerator pedal is depressed in a car, and the engine is not in an idling state, the idling rotation is controlled by feedback control. It is customary to suspend the numerical control and re-enter the feedback control only when the above-mentioned state is released.

At this time, in the conventional idle speed control device, as the basic control value of the actuator during the above-mentioned old entry, a reference value that is preset corresponding to the target speed at that time is fed back as an initial value. I was trying to start controlling it.

By the way, the reference value that is preset corresponding to this target rotation speed is uniformly set as a standard value at the time of manufacturing the device, and therefore, it cannot be used as an individual idle rotation speed control device. However, due to variations in the characteristics of the actuator and other components of each device, it is not always guaranteed that if the actuator is set to this reference value, the corresponding target rotation speed will be immediately obtained. .

Therefore, in conventional idle speed control devices, the engine speed control target value at the moment when idle speed control is entered is often different from the preset speed target value. This has disadvantages in that it takes too much time to converge to a predetermined target idle speed due to a delay in feedback control, or the idle speed drops too much and the engine stalls.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide an idle speed control device for an internal combustion engine that eliminates the drawbacks of the conventional technology, has less control delay when entering idle speed control, and does not cause engine stalling. be.

[Summary of the invention]

To achieve this objective, the present invention sets the initial value of the base position of the actuator when entering idle rotation speed control and starting feedback control to the actuator control when feedback control was previously executed. The feature is that the points are given by the average value of the positions.

[Embodiments of the invention]

Embodiments of the idle speed control device η according to the present invention will be described below with reference to the drawings.

Figure 1 d is a block diagram showing an embodiment of the present invention, in which 1 is a carburetor, 2 is a lever, and 3 is a throttle valve (pulp in the throttle).
, 4 is an intake negative pressure inlet, 5 is a negative pressure operated actuator, 6 is a bushing rod, 7 is a spring, 8 is an actuator diaphragm, 9 is a drive chamber, 10 is an atmospheric pressure opening, 11 is a valve seat, 12 is a pilot fist pulp, 1
3Lt pilot diaphragm, 14 is pilot chamber, 15 is spring, 16 is solenoid valve, 17, 18.19
is the orifice, 20 is the CPtJ (central processing unit), 21 is the power [o1 path, z2 is the ROM (read fist only memory), 23 is the RAM (random access memory), 24 is Ilo (input/output interface). 7A), 25 is a control circuit, and 26 is an output transistor.

The lever 2 is attached to the shaft of the throttle valve 3 and rotates together with the throttle valve 3.

The throttle valve 3 is connected to the accelerator pedal by a link mechanism (not shown), and is constantly biased by a spring in the direction of the arrow in the figure. Therefore, when the accelerator pedal is free, The lever 2 rotates in the direction of the arrow until it comes into contact with the bushing rod 6 of the actuator 5, and the opening degree of the throttle valve 3 is adjusted to the bushing rod 6 of the actuator 5.
The minimum opening position is determined by the 0 position.

The negative pressure actuator 5 is composed of a pilot section and a drive section, and the respective drive chambers 9 and pilot chambers 14 are communicated downstream of the throttle valve 3 via an orifice 18, 19 and an intake port 4, and negative pressure is applied thereto. It looks like this. Also,
The pilot chamber 14 is also communicated with the atmosphere via a solenoid valve 16 and an orifice 17.

The operation of this negative pressure actuator 5 is as follows.

Since the drive chamber 9 is maintained at negative intake pressure via the orifice 18, the diaphragm 8 is pushed by the atmospheric pressure introduced from the opening 10 and moves to the left in the figure against the spring 7. Trying to displace. Then, the sheet 11 separates from the pulp 12, so atmospheric pressure increases from the sheet 1 to the drive chamber 9, and the diaphragm 8
Trying to move it back to the right.

As a result, the diaphragm 8 is displaced following the pulp 12 at t2 in order to remain at a position n such that the sheet 11 and the pulp 12 maintain a predetermined, substantially constant distance.

On the other hand, the pulp 12 is attached to a diaphragm 13, and this diaphragm 13 is displaced by the balance between the negative pressure in the pilot chamber 14 and the force exerted by the spring 15. If the negative pressure is small (close to atmospheric pressure), it will be displaced to the right, and if the negative pressure is small (close to atmospheric pressure), it will be displaced to the left. So, if the solenoid valve 16 is closed now,
Since the interior of the pilot chamber 14 approaches the intake negative pressure through the orifice 19, the diaphragm 13 moves to the right against the spring 15, and the diaphragm 8 also moves to the right, retracting the bushing rod 6 and opening the throttle valve. 3. Reduce the opening degree at the return position. Furthermore, when the solenoid valve 16 is opened, the inside of the pilot chamber 14 is communicated with the atmosphere through the orifice 17 and approaches atmospheric pressure, so the diaphragm 13 moves to the left by the spring 15, and the diaphragm 8 also moves to the left. The displacement of the throttle valve 3 in the return position becomes larger.

Therefore, as shown in FIG. 2, a pulse signal with a constant period T and a pulse width Ton that can be arbitrarily controlled is supplied to the electromagnetic valve 16, and the pulse signal ! By varying ll1Ton, the ratio of air flowing into the pilot chamber 14 from the orifice 17 and air flowing out to the intake negative pressure side through the orifice 19 will change, and the negative pressure in the pilot chamber 14 will change. It can be controlled to any value between atmospheric pressure and intake negative pressure, and the opening degree of the return position of the throttle valve 3 can be arbitrarily controlled accordingly.

In addition, in FIG. 2, the pulse width Ton with respect to the period T
The ratio expressed as a percentage is called duty, and as a result, by changing the duty of the pulse signal supplied to the solenoid valve 16, the engine speed can be controlled, for example, as shown in characteristic 27 in Fig. 3. You will be able to do this.

Next, returning to FIG. 1, the operation including the control circuit 25 will be explained.

The CPU 20, ROM 22, and RAM 23 operate as a microphone computer and store various data representing engine operating conditions such as engine speed and engine temperature.
1024, performs arithmetic processing based on it, and outputs it to the transistor 26 via the output circuit 21.
y is output to control the solenoid valve 16.

When it is detected that the engine is in an idle state, the duty of the pulse signal to be output to the transistor 26 is changed according to the engine speed, as shown in FIG. Feedback control is performed to converge within a predetermined band.

By the way, at this time, there are variations in the characteristics of the actuator 5, and there are also variations in dimensions in the mounting position with respect to the carburetor 1, so the engine rotation speed characteristics with respect to the duty of the pulse signal are different for each control device. For example, as shown in characteristics 27, 28, and 29 in Fig. 3, the required Uty is also D for the target rotation speed 30
The result will be something that changes within the range from A to Du.

However, when -feedback control is performed, even if there is such a difference in characteristics, the duty of the pulse signal is adjusted in the direction where the target rotation speed and the actual rotation speed match, as shown in Fig. 4. is controlled, so there is no problem at all, but the moment you enter feedback control from a state where idle speed control is not being performed, set the duty of the pulse signal to a reference value and set it. Feedback control must be started as an initial value, and for this reason, for example, assuming characteristic 27 in FIG.
The initial value of ty. Suppose we have set it as follows.

This will not cause a problem in a control device where the characteristics obtained by the actuator are as shown at 27 in Figure 3, but in a device where the characteristics are as shown in 28 in Figure 3, for example, feedback control may occur. The instant I did it, I felt stiff. The rotation speed obtained in response to this becomes a value of 31, which is considerably larger than the target rotation speed of 30, so it takes time to converge to the target rotation speed of 30 through feedback control. Therefore, for example, in a device with a value of 29 in Figure 3, △ is the initial value. The rotational speed becomes 32, which takes time to reach the target value, and there is a risk of engine stalling, and if this continues, the same drawbacks as the conventional example described above will occur.

Therefore, in this embodiment, the control circuit 70 shown in FIGS. 7 and 8 is controlled by a microcomputer provided in the control circuit 25.
- The operation shown in the chart is executed to avoid the above-mentioned drawbacks, and the operation will be explained below with reference to FIGS. 7 and 8.

First, FIG. 7 shows the CPU 20, ROM 22. RAM23
This is an example of a processing program executed by a microcomputer consisting of a computer, etc., and serves as a management program, and is activated at a fixed cycle, for example, every 1 (+mS).

Further, FIG. 8 is an embodiment showing in detail only the feedback processing part of the process of FIG. 7.

Now, when entering the process shown in FIG. 7, first, in step 100 (hereinafter abbreviated as step S), the engine cooling water temperature and rotation speed are acquired, and in the next step (8110, the target engine rotation speed No. corresponding to the cooling water temperature is input). The basic control duty DtW is searched from the table shown in FIG. 6 at 8120. Next, 8130 and 51
At step 40, it is determined whether or not the car is running. That is, 513
At 0, it is checked whether the transmission gear is in neutral or the clutch is disengaged, and from this it is determined whether or not there is a driving force connection between the output shaft of the engine and the wheels of the vehicle. At 8140, the vehicle speed is checked. It is determined whether or not the car is running based on data from sensors, etc., and when the result in either step is Y (Bs), it is determined that the car is in a running state.

If the result at 5130 or 5140 is Yes, the process branches to 8150, and it is checked at 8150 whether or not the 7 lag 8t1 is set. This flag st1 is 5 which will be described later.
270, and therefore 5
tl-1 indicates that feedback control has been performed at least once after one engine start, and thereafter does not change until the engine is stopped.

When the result in 8150 is Yes, the process passes through 8160, adds the average control duty Dfbm to the basic control duty I)tvr, and sets the control duty Dw.
If the result at 5150 is NO, it passes through 5170 and changes the basic control duty Dtw to the control duty DW.
Set as .

Then, at 8180, the table shown in Fig. 6 is searched from the water temperature Ty, and the control duty lift amount Dupb corresponding to the engine water temperature is determined, and it is set to the up duty Dup, and at 5190, it becomes the waiting time when entering the feedback process. Set time T0 to counter Tcnt.

And in 5200, feedback processing 7 lag 5trL
Clear the feedback control duty Df at the same time.
Clear b as well.

Next, return to 5140, and if the result in 5130 and 5140 is also NO, proceed to 8210, and in this 5210, a certain amount ΔDu is subtracted from the up duty Dup, and it is set as a new up duty Dup. After that, it enters 5220 and checks whether the up-duty Dup is greater than zero, and while the result is NO, it passes through 5230 and sets the up-duty Dup to zero, and if the result is Yes, it skips 8230. , 5210 results in a new update utility Dup.
This prevents the value from becoming a negative value.

At <8240, a predetermined constant value Δtcnt is subtracted from the data of the counter Tcnt to create a new counter Tant, and at 5250 it is checked whether or not it is greater than zero.
Branches to 8280 while Tcnt is greater than zero, but
When the result at 5250 is NO1 and the counter Tcnt becomes zero or less, the process moves to the next step 8260, where the engine rotation iN (actual rotation speed) becomes the target rotation speed N. It is checked whether the value (N - No) that exceeds the above is greater than a predetermined judgment value Nα, and if the result is Yes, the process branches to 5180, and only when the result is No, the process proceeds to 5270 to perform feedback processing and provide feedback. The control duty Dfb is calculated and merged after 5200. Note that, for example, 10100-2oo (rp) is selected as the Nd value.

Following 8200, at <8280, the solenoid valve 16 (first
The control duty Dut-7 to be outputted to the control duty D is calculated by adding the up duty Dup, which is correction data, and the feedback control duty Dfb to the control duty D.
1 (Fig. 1) and exits the process according to this flow.

Next, the feedback processing at 8270 will be explained with reference to FIG.

This FIG. 8 is an example of processing for realizing the feedback control of the idle speed as shown in FIG. When the lower limit value N7 of the band is exceeded, the Duty is increased from then on, and conversely, when the engine speed N exceeds the upper limit value Nu of the target band as shown at time t, the Duty is increased from then on.
y is gradually decreased, and at this time, the increasing speed and decreasing speed of Duty are the same rotation speed N and target rotation speed N. It changes according to the deviation Nd from the
The speed of increase and decrease of
0, the table is searched using the deviation Nd to obtain the control interval number twα, and it is determined at 8510 whether or not this data Iw(Z has become smaller than the count value tc. If the result is Yes, the data 'wα is passed through 5520. set to %t.
While the result is No, 5520 is skipped.

At 5530, it is checked whether the state 7 lag 5tcL is 1 or not, and when the result is NO, the process proceeds to the rotation lowering process from 5550 to 5610, and when the result is Yes, it is checked from 5640 to 570.
Starts execution of rotation increase processing to 0.

Now, if the flag Stα is 0 at time t, the result at 5530 will be NO, and the continuation <85
At 40, the result becomes Y6s, and the process proceeds to 8580, where a predetermined constant value Id is added to the feedback control duty Dfb to form a new feedback control duty Dfb, and thereafter, the process passes through 5590 and sets 7 lag Stα to 1. Therefore, when the program is started next and starts processing this flow, the result at 5530 will be Y6.
s and enters the rotation increase process. Therefore, when the 7-lag Stα is 1 at time t1, the result immediately becomes Yes at 5530, and the rotation increasing process begins.

When starting the rotation increase process, it is first checked at 5640 whether the engine rotation speed N has reached the upper limit value Nu of the target band, and while the result is No, the process advances to 5650, and at 8650, the count value tc or 61 is checked. , and set a new count value tc, then check whether the count value tC is greater than zero at < 8680, and only when the result is No, 569
0 and 5700, and when the result is Y6s, 5
690 and 5700 are skipped.

At 5690, a new feedback control duty Dfb is set by adding a constant value Id to the previously obtained feedback control duty Dfb, and then <870
At 0, the control interval number tWa is set to the count value tc.

Therefore, while the result at 8530 is Y6g and the rotation increase processing is being performed, and the result at 8640 is NO, the processing according to 8680 to 8700 is performed from 8650, and the control interval number twcL is 1. Sometimes, every time this 70- is entered, a constant value Id is added to the feedback control duty Dfb through 8690, and the rotation speed is increased at a high speed, and as the control interval number tWα increases, the number of times 8690 is skipped. Since this increases, control is performed to slow down the speed at which the rotational speed increases.

In this way, when time t2 in FIG. 4 is reached, the result at 8640 becomes Y6s, so at this time, turn to 8660,
Contrary to 5690, this 8660 subtracts the constant value d and sets the status flag StQ to 0 when continuation<8670, so the next time this flow is entered, the result at 5530 will be No, and from then on, Until time t is reached, the process continues to lower the rotation.

In the rotation lowering process consisting of 5540 to 5610, the calculation of the new foot check control duty Dfb at 5600 is a subtraction of a constant value Id from the previous duty Dfb, and the opposite is added at 8580. is different from 5690 and 5660 in the rotation increase processing, and in S 590 and 8670, state 7 lag a
Since only the set of tα is reversed, detailed explanation thereof will be omitted.

In this way, after going through step 5720 of the rotation increase processing or rotation lowering processing, the process proceeds to 558
The average control duty Dfbm is calculated based on the new feedback control duty Dfb calculated in steps 0, 5600, 8660, or 5690, and then, in 8740, 7 lag St 1 is set to 1 and this 70- Exit the processing according to. Therefore, if the engine starts operating and enters the feedback process even once, the 7 lag St1 remains set to 1 and the 5815
The result for 0 (Fig. 7) will be No only while the feedback process has not started even once after the engine starts operating, and once the feedback process has been performed, the result will be No.
The control duty Dy is always Y6s until the engine is stopped, and the control duty Dy is the average control duty D obtained by feedback control with respect to the basic control duty Dtw.
This is corrected by adding fbm, and even if there are variations in the characteristics or mounting condition of the actuator 5 (FIG. 1), correct idle rotation speed control can be performed.

By the way, in the embodiment shown in FIG. 7, the up-duty Dup is set by providing 5180, so that the time t is set as shown in FIG. While the car is in the running state from I to time '11, the up duty Dup is added to the basic control duty Dtw.
When it is determined in step 140 that the vehicle is out of the running state, the up-duty Dup is increased by ΔDup in step 5210.
If the lower limit of the duty Dup is determined at 5220, and if it is negative, the duty D is lowered at 5230.
Performs processing to set up to O, and at 5240 counter Tc
nt is subtracted, and while the counter Tent is positive, it is 52.
50 branches to 8280, thereby allowing a waiting time so as not to immediately enter the feedback process even when idle rotation speed control becomes possible.

In the embodiment shown in FIG. 7, the waiting time T is 8250.
When o has elapsed, the process advances to 8260, where the engine rotation speed N is the target rotation speed N. It is determined whether or not the value is greater than a predetermined value Nα, and while the value is greater than the value Nα, the engine is in a dry operation from time hl to time '31 in FIG. It is assumed that the accelerator is being operated when the accelerator is not pressed, and the process branches to step 5180, thereby controlling the control duty in a sawtooth pattern from time '21 to t□ in FIG.

In a car engine, when it is in an idling state, it may be revved by operating the accelerator, and if it is rotated at high speed in such a no-load operating state, the accelerator may be pressed due to the rotational inertia of the engine. Even if it is returned, the high speed rotation state continues for 1 to 2 seconds. Therefore, if you immediately enter feedback processing at this time and control the rotation speed by closing the throttle valve, the engine will tend to stall when the inertia force disappears, making it impossible to achieve stable idle rotation. Put it away.

However, according to the above embodiment, even when the feedback process starts, the feedback process is not started for a certain period of time, and furthermore, the actuator control is stopped during driving so that the rotation speed does not drop abnormally when the feedback process starts. Since the position of the engine is displaced by the up duty Dup and the control duty is gradually decreased during the waiting state when the feedback enters, it is possible to eliminate the risk of engine stalling, etc. A stable idling state can be achieved even when the engine is revving.

By the way, in the above embodiment, as is clear from FIG. 1, a negative pressure actuator 5 is used, but this actuator may be of any type, such as an electric actuator using a motor. Needless to say.

In addition, in the above embodiment, in order to control the rotation speed of the engine in the idle state, a method of controlling the opening degree of the return position of the throttle valve is adopted, but a control valve is provided in a passage that bypasses the throttle valve. This control valve may be controlled by a suitable actuator, and one embodiment of the present invention using such a system is shown in FIG.

In this FIG. 9, 30 is a bypass passage of the throttle valve 3;
31 is a control valve, and the rest is the same as the embodiment shown in FIG.

The control valve 31 is attached to the rod 6 of the actuator 5, and when it is moved from side to side in the figure by the actuator field diaphragm 8 via the orad 6, the amount of intake air passing through the bypass passage 30 changes, thereby controlling the idle rotation speed. can do.

〔Effect of the invention〕

As explained above, according to the present invention, the initial control value when the vehicle changes from the running state to the engine idling state and enters the feedback process is automatically set to the optimum value for each device. In addition to the shortcomings of the conventional technology, it is possible to prevent variations in control characteristics even if there are variations in actuator characteristics, and the idle speed control can be performed accurately and stably, and variations in characteristics due to mass production can be automatically corrected. Since this is absorbed, it is possible to easily provide an idle speed control device with excellent characteristics at low cost.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the idle speed control device according to the present invention, FIG. 2 is a waveform diagram for explaining control signals, and FIG. 3 is a characteristic diagram showing the relationship between control duty and engine speed. Fig. 4 is a characteristic diagram for explaining the idle speed control operation by feedback control, Fig. 5 is a characteristic diagram showing the operation of an embodiment of the present invention, and Fig. 6 is a characteristic diagram used in an embodiment of the present invention. Table characteristic diagrams, FIGS. 7 and 8 are 70
-Chart, FIG. 9 is a block diagram showing another embodiment of the present invention. 1... Carburizer, 2...--Lever, 3...
... Throttle valve, 5 ... Negative pressure actuator,
16... Solenoid valve, 25 control circuit, 30...
...Bypass passage, 31... Control valve. III Figure 112 Figure 11311 No. 4 wJ Figure 5, Kaigao Tsuba 116 Figure 8 fP water, JxTw No. 71:lli Figure 8 519 Continuation of page 1 Applicant Hitachi O 1 - Motive Engineering Co., Ltd. 3085-5 Higashiishikawa Nishifurouchi, Katsuta City

Claims (1)

[Claims] 1. In an idle speed control system that is equipped with an actuator for controlling the amount of engine intake air in an idle operating state and performs feedback control of the idle speed of the engine to a predetermined target value, feedback control is executed. Means for detecting and storing an average value of control data for the actuator in the controller is provided, and when the feedback control is started from a feedback control rest state, the feedback control is started using the average value as initial control data for the feedback control. An idle rotation speed control device characterized in that it is configured to λ The idle speed control device according to claim 1, characterized in that the device is configured to provide a predetermined time delay before starting feedback control after the engine returns to a state in which idle speed control is possible. . 3. In claim 2, after the feedback control for the engine enters a rest state, the control position of the actuator is moved by a predetermined amount from the position determined by the initial control data in the direction of increasing the intake air amount; An idle rotation speed control device characterized in that the idle rotation speed is returned to the position determined by the initial control data at a predetermined speed during a predetermined time delay.