JPS5965540A - Engine idle speed control device - Google Patents

Abstract

PURPOSE:To make it possible to take up a change with age and dispersion of an engine and as well to enhance the reliability thereof, by providing such an arrangement that the control gain of a control system is made to be variable upon engine ilde speed control, and is renewed with an optimum control gain obtained at the last time. CONSTITUTION:An air volume adjusting valve 13 is disposed in a bypass passage 12 bypassing a throttle valve 10 and connected to an intake air passage 3, and is driven and controlled by a drive device 14 controlled by a micro-computer 15 which, in this arrangement, comprises an RAM25 for storing the control gain of a control system. In order to converge the actual engine speed which is detected by an engine speed sensor 18, to a desired engine idle speed which is established in accordance with the outputs of a water temperature sensor 16 and a cooler switch 20, a control signal for the drive device 14 is delivered in accordance with the control gain read out from the RAM25. Further, the control gain is compensated so that the control system may have a predetermined function, and the thus obtained compensated gain is used for the next control.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention includes a regulating valve drive device that opens and closes a regulating valve that regulates the amount of intake air supplied to the engine, so that the idle speed during idling converges to the target idle speed. This invention relates to improvements to the idle rotation side (FLL) device of the engine that controls the regulating valve drive device.

Conventionally, this type of idle speed control device has been known, and if the engine is cold but warmed up, or is equipped with a cooler, the cooler is turned on even if the engine is warmed up. Depending on the engine operating condition, such as whether the engine is running or not, set a target idle speed as low as possible within a range that does not cause engine stalling or unpleasant vibrations due to misfire, and converge the actual idle speed to that target idle speed. This is intended to improve fuel efficiency during idling operation.

By the way, in the conventional idle rotation control device, the control gain of the control system is kept constant, and the control gain is adjusted using this constant control gain.
A control method is used to control the drive device, and it is actually very difficult to set the control gain value appropriately.
There has been a problem in that it is difficult to converge the idle speed to the target idle speed in a responsive and stable manner.

That is, from the standpoint of stability of NQ control, it is preferable to set the control gain value relatively small to reduce the fluctuation range of the idle speed, but Fig. 6 (A) shows the change in the idle speed. For example, if the cooler is turned on during idling and the engine load increases and the rotation speed drops rapidly, the control gain is small and the adjustment cannot increase the rotation speed in time, resulting in the engine stalling. In extreme cases, when the rotation speed drops below the critical engine stall danger number NL, the actual engine stall may occur or unpleasant vibrations may occur.

Therefore, in order to improve control responsiveness, conversely, the control gain value should be set large and the amount of adjustment per time should be increased (
It is preferable to take this setting, and if such a setting is used, σ3 in FIG.
), even if the cooler load is suddenly applied during idling, a large drop in the idling speed can be avoided, but because the control gain is large, large fluctuations in the idling speed occur and the desired convergence is prevented. There is a problem in that a so-called hunting phenomenon occurs in which vibration exceeds the range (indicated by a thin line in the figure), and necessary convergence (stability) cannot be obtained.

In order to deal with this problem, two control gain values, large and small, are determined in advance, and if the deviation between the actual idle speed and the target idle speed is large, the larger control gain value is selected and An idle rotation control method has been proposed in which the response is increased by increasing the amount of adjustment, and when the deviation becomes small, a small control gain value is selected to obtain the necessary convergence (Japanese Patent Application Laid-Open No. 1983-1999). (See Publication No. 142944).

However, there are variations in engine performance even between engines with the same specifications, and changes in engine performance occur even after so-called aging, so for example, two control gain values, large and small, are selected as shown above. Even if a method that uses a target value is adopted, and even if the control gain value is set appropriately, it is possible to effectively deal with variations in the angle of the curve (also, this θ). There is a problem in that the idle speed cannot be effectively controlled, and the idle speed cannot be properly controlled after long-term use.

The present invention has been made to solve this problem, and the control gain value of the control system is made variable, for example, when the idle speed was converged to the target idle speed during the previous idling operation. By using the control gain value as the initial value for the current idling operation, the control gain can be updated at any time according to changes in the engine over time and variations. An object of the present invention is to provide an engine idle rotation control device that can simultaneously satisfy the requirements for both control responsiveness and stability.

Therefore, the present invention (in this case, a storage device that rewritably stores the control gain value of the control system, and a control gain value stored in the storage device) is used to determine the actual idle speed and operating state. The control valve driving device is controlled so that the idle speed converges to the target idle speed based on the comparison result with the target idle speed set according to Modify and change the above control gain value to obtain stability, and find the optimal control gain value.
In order to use this control gain value for the next control, we basically installed a control circuit that rewrites the 11 control gain changes stored in the storage device with the obtained control gain value. It is a characteristic feature. Here, if the content stored in the storage device is j- so that it will not be erased even if the engine key switch is turned off, the control gain f+-i stored in the storage device will be the same as that in the previous idle rotation control. This is the finally obtained optimum value for the quantity, and it faithfully reflects the most recent engine condition. By using this control gain value as the initial value when controlling the idle speed, it is possible to obtain a very early It is possible to converge the idle rotation speed to the target idle rotation speed response with good stability. In other words, even if it is necessary to modify the initial stage,
[E time can be made as small as possible, and the responsiveness and stability of the idle rotation control Ml system can be improved.

In addition, the idle rotation system i! In the III device, there are two ways to adjust the intake air; A method is known in which a bypass passage is provided, a valve is provided to open and close this bypass passage, and the opening and closing of this valve is controlled 11111, and the present invention can be applied to both methods. In other words, the regulating valve according to the present invention may be a throttle valve or a valve provided in a bypass passage, and in the case of a throttle valve, the regulating valve driving device controls the opening of the throttle valve t. It is a device that adjusts the degree of
In the case of a valve provided in a bypass passage, a device that drives the valve f constitutes a regulating valve drive device.

The present invention will now be described in more detail based on the illustrated embodiments.

In the i1 diagram, l is the engine and 2 is the piston.

:( is the intake passage of engine 1, 4 is the ljl of engine 1
Air passage, 5 is combustion, 6 is I"t' which burns intake passage 3.
+i 51 Intake valve that opens and closes with respect to 7, 111 precept passage 4 with rr'<
It is.

The intake passage 3 includes an air cleaner 8. An air flow sensor 9 that detects intake air and a throttle that is connected to an accelerator pedal (not shown) set lO, and L'lAt of a throttle valve 10 on the downstream side of the airflow sensor 9 indicates fuel s'. ] The injection valve lt+ is installed facing the intake passage 3.

Furthermore, the intake passage 3 is provided with a bypass passage 12 that bypasses the throttle force 10 and communicates the upstream side and the downstream side thereof.
A regulating valve 13 is provided to regulate the bypass air jd flowing through the valve 2, and the regulating valve 1113 is driven by a regulating valve driving device 14 which is not specifically shown in the drawings but which operates a step motor and a suitable transmission system.

A drive signal corresponding to the step motor number of the regulating valve drive device 14 is transmitted to a microcomputer 15 as a control circuit.
The basic principle is that during idle operation, when the idle speed is lower than the idle speed, the opening of the regulating valve 13 is increased to increase bypass air ventilation. By increasing the light 11'[:1[, the rotation speed is increased to 1], while when it is higher than the target idle rotation speed, the opening degree of the regulating valve 1;3 is reduced to reduce the bypass air ventilation. Feedback control is performed according to the rotation speed to reduce the idle rotation speed.

l-Microcomputer 15J Airflow Make 9
The intake air meter detected by c, and the cooling water 2i'uj of the engine 1 detected by the water temperature sensor 161.
Rotation sensor '18 built into the distributor 17
Engine rotation speed detected by / Throttle valve opening detected by opening sensor 19 / -ra switch 2
o's on/off signal is used as long-term data, and based on these long-time data, a drive number 13 is outputted to the fuel injection valve 11, and when the engine 1 is idling,
Output the N8 motion correction υ to the regulating valve drive device 14, and set the idle rotation speed to 1:1.
V, control the bugs.

This microcomputer 15 has an I10 interface 21. Medium heat ih't'p: 9! L immediately, 1, set (C11Ll) 22, read-only memory (R (fusuma)
23. First random access memory (r It A
M) 24 + KS2-j consisting of volatile memory
data bus and address bus (not distinguished in the figure).
The basic structure connected to +11 by the lotus 26 is expressed as (''I).

Next, the microcomputer 15 calculates the idle rotation i1;
Bi (theory 1 is J.

As shown in Figure 4, the eye size (idle rotation/number of people)
t:1 is set in two ways depending on whether the cooler is turned on or off as a function of the engine cooling water temperature.
The target idle speed N SJ and 1 are determined from the engine operating conditions.
Restore IZ and necessary data to make settings according to whether V is on or off. In addition, a second
A part of the RAM 25 serves as a storage device according to the present invention, and is stored so that the control gain 116K can be rewritten and the memory value is not erased even when the power is cut off.

Now, when the engine 1 starts idling, the microcomputer 15 executes idling rotation control according to the control flow shown in FIG.

As shown in FIG. 2, the microcomputer 15 performs an initial reset in response to the start signal, and sets the integrated value M of the deviation between the target idle speed Ns and the actual engine speed NrP1n and the sampling number 11 to zero, respectively. Set (step S1).

Next, in step S2, it is determined whether or not the engine is in idle operation based on the engine rotation speed detected by the rotation sensor 18 and the throttle valve opening detected by the opening sensor 19i. After activating the built-in sampling timer (not shown), in step S3, the stator indicating the engine operating status such as cooling water temperature, cooler on/off, etc. is sent to the I10 interface 21.
In step S4, the target idle rotation speed N81-1 (see FIG. 4) is calculated by the CPU 22 from the read engine operating state using the data in the RUM 23.

Next, in step S5, the actual engine rotation speed (rl)ITI detected by the rotation sensor 18 is set to the lRA.
M24 is loaded, and in step S6, the target idle speed "S E'l-" and the actual engine speed N r l
□,.

The integrated value of deviation from M-(NSJ!Tl' ” rpm
)+M is calculated, and in step S7, the second
The control gain value K stored in the RAM 25 is read out, the integrated value M and the control gain [K are combined, and the product 1'' is calculated. This control gain 1] is actually the optimum value obtained in the previous idle rotation control, as will be described later, and the current idle rotation control is executed with this previous optimum value as the initial value. Become.

The PIN obtained as described above is used to drive the step motor drive 11 of the regulating valve drive device 14 in step S8.
This step morph drive signal is used to drive the output method step motor via the Ilo interface 21 to set the opening 1y of the regulating valve 13.

In this case, step motor drive No. 18 has a dead zone for hunting prevention 1]2 near the plus side and minus side of P-0, as shown in Fig. 5, and when the dead zone is exceeded, It is set as the number of pulses proportional to P at the slope given by the control gain value . For the drive, the amount of displacement of the regulating valve 13 is set according to the number of pulses the signal has and the (J property).

Next, in step S9, the engine stall danger speed NL (the speed at which there is a risk of engine stall) determined based on the engine operating state ζ and the actual engine speed "rpln" are determined.
If the actual engine rotation speed Nrpm is lower than the dangerous engine stall rotation speed NL, in step 510, the control gain value K is unconditionally set to K (−K+△Kt
, increase the control gain value K by a predetermined increment m Δ by □, immediately return to step S2, and in the process from step S2 to step S8, the rewritten control gain value K (, - to +△ to □) sets the opening degree of the regulating valve 13 one step larger and increases the amount of bypass air (
, I to judge the engine speed with good responsiveness.

In addition, under normal conditions when the actual engine speed Nr 1) In exceeds the engine stall danger speed NL,
The absolute value (fluctuation range) of the deviation between the idle speed NSF, 'l- and the actual engine speed Nrpn1 is determined in advance by RO.
Whether or not it is larger than the set width α written in M23, in other words, whether the actual engine speed ``rpm'' is stable within the range of the target idle speed N5ET and the set width. It is determined in step Sll, and if the control gain value K is stable, the control gain value K at that time is the optimum value and there is no need to rewrite it, so the process directly returns to step S2.

- 10,000, if the fluctuation is greater than the set width α (unstable), the number of times n is counted in step 512,
Further, in step 513, the time ('I') is read from the activated timer. Then, in step 514, a certain time ('Vo
) has elapsed, the process proceeds to step S15, where it is determined whether the number of numberings 11 described above is greater than or less than a predetermined 111'1 (NO). ) determines how much rotational fluctuation (corresponding to the number of sampling times n) occurs within 1. In other words, the stability is within the set (W) level range. This is to judge whether it is good or bad.

When it is above the setting (,71) level range, the current system Ja (the system used for I1i111 gain
In this case, the control gain [K is updated in step 516. In this case, the update is performed using the supplementary information written in advance in the ROM 23.
: Using Iu'L△K z , the current control gain value K is decreased by 2 to Mli positive value Δ, and is reduced to K4- by -Δ2),
Using this value, the current control gain fuT K can be calculated from the second RAM.
25, and the sampling number n is set to zero again in step 517.
[Reset the 1 cup and determine the control gain 961 (1 cup and adjust the control gain by the next sampling)!*7F13
Adjust the opening.

” If the necessary stability cannot be obtained, as in item 2, a.
Since the control gain sensitivity K is changed to △ by 111j, the next control will be the rewritten control gain f1+'t
K + This will be carried out, and the next control i
i! 41 + At this point, the necessary ``consistency'' can be obtained. However, if stability within the il' trough level does not seem to be obtained after stopping - times, repeat the above steps.

In this way, when the necessary stability is obtained, the control gain at that point is 1+:t and the second
The value remains in the RAM 25, and at the next idle operation, the control gain 1/1 as the previous optimum value stored in the second RAM 25 will be used as is as the initial value. The control gain value [( as a value) reflects the latest engine information such as engine variations and aging changes, and therefore allows smooth idle rotation control in response to variations and aging changes.

If the cooler load is applied during idling operation, the value of 11αK can be increased sequentially, so the value of 11αK can be increased as shown in Figure 6 (C). The engine speed 11 can be adjusted by 1 + (-1-) 1 before it goes below the engine stall danger speed NL, and if this control gain 11't K increases too much, i1r control publication? :# Since it is possible to reduce Ii'EK to δ1, it is possible to reliably prevent the so-called hunting current use11], and the fluctuation 1111",
1 can be stabilized as quickly as j&lJ within the range of 1α.

Next, another idle rotation control method of the present invention will be explained in the third example.
The idle rotation control flow shown in FIG. 3 is a modification of the convergence determination method in steps S11 to 5171 of the control flow shown in FIG. This method uses a type of integral control method to perform easterness determination.

That is, in step 511, the target idle rotation speed N
Absolute f-direction of deviation 7θ between s+, t・ and actual engine speed Nrpnl (1"5E-1-" rpm I)
is pre-sealed a2 fixed t.

If the variation range α is larger than 1'+f, the absolute value of deviation 7J is calculated in step 512 by 1110th f.
Going through 4 prefectures (S"I"SE'I"-"rpnl
+"),Suff7"S13'.

At step 514, as in the case of FIG. 2, it is determined whether or not the setting/limbling time "blank 0" has elapsed. After that, in step 515, when the integration l1ifS exceeds the preset determination value (quasi Ii & So), it is determined that the necessary stability has not been obtained, so in step S16
8 and update the control gain (lαl() to 1(・I(−
/＼Iku. ).

At step 517, the integrated value S is set to zero, and
The sampling timer is reset and the rewritten control gain nu +< is used for the next control loop.

Incidentally, regarding the flow shown in FIG. 3, Step 5l-sh except that the absolute deviation: AJ fu't integration 6αS is set to zero upon initialization in Step Sl.

Since there are no changes in the steps in this embodiment, a description thereof will be omitted.

As is clear from the above description, according to the present invention, the control gain value of the control system is made variable in idle rotation control, and the 11α is updated to the optimal control gain value obtained last time. It is effective in dealing with aging and variations in the engine, and since the updated control gain value is used for this idle rotation control, it is possible to improve the responsiveness and stability of the control. Benefits can be obtained.

[Brief explanation of drawings]

FIG. 1 is an overall explanatory diagram showing an embodiment of the present invention, and FIG. 2 is a flow diagram showing an idle rotation control flow according to the present invention.
- Fig. 3 is a broach -'t' -) diagram showing the idle rotation control flow of the song, Fig. 4 is a graph showing an example of setting the target idle rotation speed, and Fig. 5 is a step of the regulating valve drive device. Graph showing the control characteristics of the motor, see Figure 6), Φ),
0 is a graph showing how the idle rotation speed changes when the cooler is turned on, respectively, for the conventional and the present invention.

Claims (1)

[Claims] (,1,) -] = rotational speed detector that detects the number of carrots, a regulating valve drive device that opens and closes the regulating valve that regulates the intake air Φ supplied to the engine, and a control gain of the control system 1 The target idle speed set according to the operating state and the actual idle speed detected by the rotation speed detector are inputted into a storage device in which the rotation speed is stored and the detection signal of the above-mentioned rotation speed detector. Based on the comparison result, a control signal is generated to operate the regulating valve drive device so that the actual idle speed converges to the target idle speed using the control gain value stored in the Kitaki storage device. On the other hand, when the control system has a predetermined response,
The final control gain value is obtained by correcting it to obtain stability, and the value in the storage device is written to the final control gain value. From next time onwards, control will be performed using this control gain value. An engine idle rotation control device comprising a control circuit as described above.