JPS58158343A - Controlling method for number of idling revolution - Google Patents

Abstract

PURPOSE:To memorize proper learning value at all times by correcting learning value as initial value in case of the starting of the control of an idling-speed control valve on the basis of deviation with control value during the feedback control of the number of revolutions and using the corrected value as novel learning value. CONSTITUTION:An electronic control circuit controlling the idling-speed control valve (ISCV) starts the feedback control of the number of idling revolutions at a step 42 when the formation of the conditions of idling is decided at a step 41, and varies the control value D of the ISCV. Whether or not the number of revolutions NE is larger than value obtained by adding predetermined value alpha to target value NF is decided at a step 43, whether or not control value D is smaller than learning value DG is decided at a step 44 when the number of revolutions NE is larger, and learning value DG is brought to value from which prescribed value G1 is subtracted at a step 45 when control value D is smaller. When the formation of a formula NF+alpha>NE>=NF is decided at a step 47, value subtracted at a step 49 shall be G2 (G2<G1).

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for controlling an engine speed during idling, that is, an idle speed, and particularly to an idle speed control method for learning a control value of an idle speed control valve during feedback control.

In recent years, with the deterioration of the energy situation, the demand for lower fuel consumption in automated vehicles has increased, and in conjunction with the tightening of exhaust gas regulations, various methods have been proposed. One such method is to precisely control the idle speed according to various conditions under which the engine is placed, such as intake air temperature and engine cooling water temperature.

This method is usually referred to as an idle speed control system (hereinafter referred to as ISO), and attempts to control the idle speed to a target value, that is, the target speed by feedback, by adjusting the amount of air flowing into the bypass path of the throttle valve during idle. It is something.

In the above-mentioned ISO, the IIJill value of the idle speed control valve (hereinafter referred to as l5CV) during feedback control is stored as a learned value, and this learned value is used as the l5 value when starting the next feedback control.
So-called stroke control, which is used as a CV control value, was performed.

However, if you simply store the 1SCV control value during feedback control, the 15CV control value may differ from the ideal value due to disturbances such as power steering activation, and the idling speed will change every time you idle. There was a problem that the idle link was unstable due to changes.

An object of the present invention is to provide an idling speed control method that solves these problems.

This purpose is to control the air flow passing through the idle speed control valve by feedback control, to maintain the engine speed during idling at a target value, and to use the control value of the idle speed control valve during the feedback control as a learning value. In an idle rotation speed control method in which the learned value is stored and used as an initial value of the control value when starting feedback control after the next start, the control value during the feedback control is a value different from the already stored learned value. Achieved by an idle rotation speed control method characterized by correcting the learned value by a correction value corresponding to the difference between the idle rotation speed and the target value, and storing the corrected result as a new learned value. be done.

The present invention will be explained below by giving an example and referring to the drawings.

First, FIG. 1 is an explanatory diagram showing an engine and its peripheral equipment to which the method of the present invention is applied.

1 is the engine body, 2 is the piston, 3 is the spark plug, 4
5 is an exhaust manifold, 5 is an oxygen sensor provided in the exhaust manifold 4 and detects 1 degree of residual oxygen in the exhaust gas, 6
1 is a fuel injection valve that injects fuel into the intake air of the engine body 1, 7 is an intake manifold, and 8 is an intake manifold 7
9 is a water temperature sensor that detects the temperature of engine cooling water; 10 is a throttle valve; 11 is linked to the throttle valve 10; 10
12 is a bypass passage which is an air passage that bypasses the throttle valve 10; 13 is a bypass passage which controls the opening area of the bypass passage 12; CV114 is an air 70 which measures the intake air. -Meters 15 and 15 respectively represent air cleaners that purify the intake air.

Further, 16 is an igniter that outputs the high voltage necessary for ignition;
7 is a distributor that is linked to a crankshaft (not shown) and distributes the high voltage generated by the igniter 16 to the spark plugs 3 of each cylinder; 18 is installed inside the distributor 17, and is connected to the crankshaft for one revolution of the distributor 17, that is, the crankshaft; A rotation angle sensor that outputs a pulse signal 24 times per 2 rotations, 19 is 1 of the distributor 17
Cylinder discrimination sensor that outputs a pulse signal once per rotation, 2
0 represents an electronic control circuit, 21 represents a key switch, and 22 represents a starter motor.

Furthermore, 23 is the throttle pal when the engine is cold.

This shows a passage for air to flow around the valve, that is, a fast idle bypass passage. Reference numeral 24 indicates an air valve for controlling air passing through the fast idle bypass passage 23. Note that the air valve 24 operates to open the fast idle bypass passage 23 in order to secure the engine rotational speed necessary for warm-up operation when the engine is cold.

Referring now to FIG. 2, a block diagram of an electronic 1IllI111 circuit 20 is shown.

30 is a central processing unit (hereinafter simply referred to as CPLJ), 31 which inputs and calculates data output from each sensor according to a control program and performs processing for controlling the operation of various devices such as 15CV13;
32 is a read-only memory (hereinafter simply referred to as ROM) in which the control program and initial data are stored, and 32 is a random access memory (hereinafter simply referred to as ROM) in which data input to the electronic control circuit 20 and data necessary for arithmetic control are read and written. 33 is a backup random access memory (hereinafter simply referred to as backup RAM) backed up by a battery so as to retain data necessary for engine operation even when the key switch 21 is turned off; 34 is not shown; There are no input ports, waveform shaping circuits provided as needed, and output signals from each sensor to the CPU.
30 respectively represents an input section equipped with a multiplexer for selectively outputting 1-, an A/D converter for converting an analog signal into a digital signal, and the like. Reference numeral 35 represents an input/output unit provided with an output port in addition to an input port (not shown), and a drive circuit etc. that drives 1scV13 etc. according to a control signal from the CPU 30 as required, and 36 represents a CPtJ30. ．． It represents a path line connecting each element such as the ROM 31, the input section 34, and the input/output section 35, and through which various data are sent.

Next, FIG. 3 is a flow chart showing a control program for feedback learning control of this embodiment, FIG. 4 is a flow chart showing a control program for the "guard processing" routine in FIG. 3, and FIG. 5 is a flow chart showing a control program for the "guard processing" routine in FIG. The operation of this embodiment will be explained below along with each flowchart.

First, in FIG. 3, the key switch 21 is turned on, and a "feedback (hereinafter simply referred to as F/B) learning control" routine processing is started at a predetermined timing, and in step 41, the ISC F/B control is performed. Conditions such as whether the throttle is fully open according to a signal output from the throttle position sensor 11, or that the vehicle speed is zero according to a vehicle speed sensor (not shown), etc.
It is determined whether or not the condition (hereinafter simply referred to as F/B condition) is satisfied, and if the determination result is rNOJ, the process moves to the "guard processing" routine shown in 46, and if the determination result is "rYFS",
The process moves to step 42 for F/B control.

In step 42, the learning value DG already stored in the backup RAM 33 is set as the control ID.
Output to 3. Suru! : The I SCV 13 is maintained at the opening degree according to the control value, and as a result, the bypass path 12
The air passing through the engine is controlled so that the idle rotation speed is controlled according to the amount of air. Further, when the rotational speed NF at this time is different from the target value NF, processing is performed to increase or decrease the control 1111iD of the l5CVI3 in order to bring the idle rotational speed closer to the target value NF.

Next, in step 43, the idle speed NE is set to [Target I
It is determined whether or not N F , (-α(α〉O)" or more, and if the determination result is rYEsJ, the process moves to step 44, where the magnitude of control (11) D and learning value DG is determined,
[If D≦D G J, supplement 1E (ll
fGl is subtracted, the result of the subtraction is stored as a new learned value DG, and then the process moves to the "guard processing" routine shown in 46. On the other hand, if rD>DGJ, no correction is made to the learned value DG. Process [Proceed to routine 46].

Then, in step 43, if the idle rotation speed NE is smaller than r N F +α], in step 47, the idle rotation speed NE and the target rotation speed NF are further compared in magnitude. In this step 47, rNE≧NF
If it is determined to be J, the magnitude of the control value and the learning value DG is determined as in the process in step 44, and "D≦D" is determined.
If GJ, the correction value G2 is subtracted from the learned value DG, the result of the subtraction is stored as a new learned value DG, and the process moves to guard processing 1 routine 4'6, and in step 48
If it is determined that D>DGJ, the process moves to the "guard processing" routine 46 without making any correction to the learned value DG.

Then, if it is determined in step 4-7 that INF<NF, then in step 50, "NE≧NF-α"
It is determined whether or not. rYE in this step 50
If it is determined that sJ, the magnitude of the control value and the learning value DG is determined in the next step 51, and if it is determined that rD<DGJ, the process moves to the "sword processing" routine 46,
If the judgment result is “NO”, that is, [D≧DGJ, the learned value D
After adding correction 11G2 to G and storing the added result as a learning value DG of 1c, "guard processing" routine 4 is performed.
Proceed to step 6.

Further, if it is determined in step 50 that the engine rotation speed NE is smaller than the "target rotation speed NF-α",
Proceeding to step 53, similarly to step 51, rD<DG
J, and if the determination result is rYEsJ, the process moves to the "guard processing" routine 46, and step 53
If the determination result is rNOj, the correction value G1 is added to the learned value DG, the added cohesion is stored as a new learned value DG, and then the process moves to the "guard processing" routine 46.

In each case, a "guard process" as described later is executed in a "guard process" routine 46, and then the process of this routine ends.

To explain in more detail the processing of this routine explained above, the engine speed is divided into four parts (NF+α, NF, NF-α), and further control is performed in each division. Cases are divided into a total of eight categories, large and small. If these divisions are illustrated, they will be as shown in (■) to [Yes] in FIG.

And, in the ■ category, Control-11D is F/Bill
As a result of all, the learned value DG is larger than the learned value DG, so the learned value DG is maintained as it is without being corrected. However, in the category of
F + α” relationship, that is, F / B III till
To.

Therefore, if the idle speed NE is greater than the target value 11IINF plus α, and the control at that time is
If the relationship is below the stored learning 1i1DG,
The learned value DG, which is the initial value of the control value of 15CV13 during the first F/8 control after the next engine start, is too large if it is already stored.

This learning value DG is used as the initial ill at the time of restart.
If used as 111m, the idle speed may be too high. For this reason, in step 45, the learned value is increased by the correction value G1.

When the idle rotation speed NE satisfies the relationship [N-cho≦NE<NF+α] in the category ■, that is, "control value DG≦learning value DG", the learning IDG is set in step 49 similarly to the category ■. is decreased by a correction value G2. Note that the correction values G1 and G2 have the following relationship: □rG1>G2J, and the magnitude of the correction value for correcting the learned value is changed in response to the idle rotation speed increased by the F/B i control. There is.

Further, regarding the category (■), similarly to the above-mentioned category (2), the learned value D'G is not corrected and is maintained as it is.

Next, in the category (■), that is, when the control value D≧Gakushin value DGJ and the idle rotation speed NE satisfies the relationship rNF>NE≧NF~α, the learned value DG is less than or equal to the control value. , first F after next startup ,,z B Ill t
The learned value DG, which is the initial value of the control value of l5CV13 at the time of ill, is too small, and there is a possibility that the next F/B control will cause the rotation to be too low or cause an engine stall. Therefore, the value of DG is increased by the correction value G2 in step 52. However, even if the idle speed NE is the same as that in the category ■, the learning I
The value of DG is maintained as it is without correction.

Then, as shown in ■, when the limit value D≧learning 11iDGJ and the idle rotation speed NE satisfies the relationship rNE<NF−α, the learned value DG is set at step 54, as in the case of the category ■. It is increased by the correction value G1. Even if the idle rotation speed NE is the same as in the category (■), in the [Yes] category where the relationship rDG>DJ exists, the learned value DG is maintained as it is without correction, as in the category.

That is, in this routine, the F/B shown in step 42
As a result of control, when the control value becomes a value that is equal to the learning value DG as in the categories from ■ to ■ mentioned above, and the idle rotation speed NE becomes a value different from the target value NF, the case 1 shown in each category occurs. Correspondingly, a correction value indicated by G1 or G2 is added or subtracted from the learning value DG to perform new learning (III
DG is calculated, and then the newly calculated learning value DG is subjected to [GART processing].

Next, the "guard processing" routine shown at 46 will be explained. In the "guard processing" routine, step 45.
49. When the newly calculated learned value DG in 52 or 54 is not within a certain range, the learned value DG is strongly replaced with the upper or lower limit value of the range, and the learned value D
Processing to prevent G from increasing or decreasing indefinitely,
I do. The "guard processing" routine will be explained below with reference to FIG.

First, in step 60, the learning value DG is set to the upper limit value DGMA.
It is determined whether or not it is smaller than X, and the determination result is rNO,I
, that is, if the learned value DG is greater than or equal to the upper limit value DGMAX, in step 62 the learned value 1)G is set to 1 shown in the upper limit value DGMAX, and the processing of this routine is completed, and the determination result is rYESJ, that is, the learned value DG If the learning value DG does not exceed the upper limit DGMAX, it is determined in the next step 61 whether learning (aDG is greater than the lower limit 11iDGMIN).The result of the determination is f'NOJ, that is, the learning value DG
If it is less than or equal to GMTN, the process of this routine is completed by setting the learned value DG to the value indicated by the lower limit value DGMIN in step 63, and if the determination result is "YES", that is, the learned value DG is the lower limit +
If the value is greater than or equal to aDGMIN, the learned value DG is maintained at the same value and the processing of this routine is completed.

That is, this routine performs a process of providing upper and lower limit guards to the learned value DG. In addition, the upper limit DGMAX,
The lower limit value DGMIN is set to an average upper limit value and lower limit value, taking into consideration variations in the engine body 1 and l5CV13.

Next, the "learning value forced set" routine shown in FIG. 5 will be explained.

This routine is a process that is performed when the key switch 21 is turned on. First, in step 7o, the backup RAM 3 is
It is determined whether the standby bit of 3 is set. If the determination result is rYEsJ, that is, the standby bit is set, the process moves to step 71, and the control value DM determined from the average characteristics of the engine body 1 and l5CV13 is stored in the backup RAM 33 as the learned value DG. to finish the processing of this routine,
Also, if the determination result in step 7o is rNOJ, that is, the standby bit is not set, the backup RA
The process of this routine ends with the learning value DG in M33 unchanged.

Note that the value D stored as the learned value DG in step 71
Since a slightly higher value of M is more reliable and less likely to cause an engine stall, it may be set to DM1β.

To explain the backup RAM 33's standby message, for example, if the battery is completely dead or if the battery electrode is removed when replacing the battery, the supply of backup power to the backup RAM 33 is cut off, so the Learning stored and retained in (aD
G disappears. In such a case, the backup power supply is cut off and the backup RAM 33 is equipped with a special signal line terminal to output information to the CPU 30 that the correct data is not stored in the backup RAM 33. , outputs a low binary standby signal.

This signal line is used as a standby bit. still,
If l5CV13 breaks down and is replaced, backup R
The learning pattern DG stored in AM33 is the l5C after replacement.
Since the value is often not suitable for V13, the standby bit may be set in such cases as well.

In the [Learned Value Forced Set] routine explained above, if data in the backup RAM 33 is lost, etc.
The average learning value (aDG) can be forcibly set, without having to calculate the optimal learning value DG by repeating control (which usually requires idling for ten minutes), so it is possible to quickly control the idle speed to an appropriate value. can do.

As described in detail above, the idle speed control method of the present invention controls the amount of air passing through the idle speed control valve by feedback control, maintains the engine speed during idling at a target value, and In an idle speed control method, a control value of the idle speed control valve under control is stored as a learning value, and the learned value is used as an initial value of the control value when starting feedback control after the next start. When the control value in the middle becomes a value different from the learning value already stored, the learning value is corrected by a correction value corresponding to the difference between the idle rotation speed and the target value, and the corrected result is used as a new learning value. It is characterized by being stored as a value.

For this reason, 15CV (7) am F/B 11 I
I ni J: When the idle speed differs from the learned value and the idle speed becomes a value different from the target value, the size of the correction value to be corrected at one time according to the difference between the idle speed and the target value. In other words, when the difference is large, the correction value can be made large, and when the difference is small, the correction value can be made small. This has the effect that an appropriate learned value can always be stored.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram showing an engine and its peripheral devices in one embodiment to which the method of the present invention is applied, Fig. 2 is a block diagram showing an electronic control circuit, and Fig. 3 is an F/B learning control of this embodiment. FIG. 4 is a flowchart showing the program of the guard processing routine, FIG. 5 is a flowchart showing the learned value forced setting routine, and FIG. 6 is the flowchart showing the program of the guard processing routine. It is an explanatory diagram showing processing contents of a control routine. 13-I S CV 21...Key switch 33...Backup RAM Agent Patent attorney Tsutomu Seitachi Fig. 4 Fig. 5

Claims (1)

[Claims] Controlling the amount of air passing through the idle speed control valve by feedback control to maintain the engine speed at a target value during idling, and storing the control tllii of the idle speed control valve during the feedback control as a learned value, In an idle rotation speed control method that uses the learned value as the initial fraction of the control value when starting feedback control after the next start, when the control value during the feedback control becomes a different value from the already stored learned value. An idle rotation speed control method, characterized in that the learned value C is corrected by a correction value corresponding to the difference between the idle rotation speed and the target value, and the corrected result is stored as a new learned value.