JPH0345224B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a control device for an internal combustion engine for an automobile, and in particular has a learning function so that control operations can always be performed under optimal control parameters. It relates to an electronic control device.

[Background of the invention]

Feedback control has traditionally been used for knocking control and air-fuel ratio control in internal combustion engines, but in recent years, in order to improve the responsiveness of such feedback control, the control value of such feedback has been changed from the reference value. Write and store the deviation data in the section in the memory map that corresponds to the operating state of the engine at that time, and use this stored data the next time the engine is in the same operating state. The so-called learning control method, which quickly controls the control value to the optimum value by correcting the control based on the It is disclosed in the official gazette and Japanese Patent Application Laid-open No. 54-57029.

An example of an engine control system using such a learning control method is shown in FIG.

This FIG. 1 shows an example of an engine air-fuel ratio feedback system, where 1 is an engine, 2 is an intake air flow rate sensor, 3 is a control circuit, 4 is an injector (fuel injection valve), and 5 is an O ₂ sensor.

The control circuit 3 includes a microcomputer (referred to as a microcomputer), and controls the intake air flow rate Q _A of the engine 1.
is detected and taken in by the intake air flow rate sensor 2, the fuel injection amount is determined accordingly, and the injector 4
is driven by the drive signal P _i to supply a predetermined amount of fuel to the engine 1.

The rich air vapor concentration is detected from the exhaust gas of the engine 1 by the O ₂ sensor 5, and a concentration signal O ₂ is input to the control circuit 3. As a result, the control circuit 3 applies feedback control to the drive of the injector 4,
To maintain the air-fuel ratio of the intake air-fuel mixture in an optimal state. The pulse width T _i of the drive signal P _i at this time is
It is determined by the following equation (1).

T _i = (K ₁ · Q _A /N · K ₂ · α) + T _S ... (1) Here, K ₁ is a constant determined by the characteristics of the injector, Q _A is the intake air amount, and N is the engine Rotation speed, K ₂ is a correction coefficient depending on engine temperature, etc.
α is an air-fuel ratio control coefficient, and T _S is a correction amount based on battery voltage.

Feedback control using the signal O ₂ from the O ₂ sensor ₅ is performed by changing the control coefficient α as shown in FIG. (also a state where the air-fuel ratio is leaner than the stoichiometric air-fuel ratio) is changed periodically to control the fuel supply amount by changing the above α.
The aim is to obtain control such that the average value of the air-fuel ratio converges to the stoichiometric air-fuel ratio (approximately 14.7), and in an ideal state where the air-fuel ratio that is the basis of control is correct, the value of α is It oscillates around 1.0, and the average value of the air-fuel ratio matches the stoichiometric air-fuel ratio.

If the air-fuel ratio deviates from the stoichiometric air-fuel ratio for some reason, the center value of the control coefficient α is shifted in the direction to correct it by O ₂ feedback control. For example, if the air-fuel ratio becomes 10% richer, in order to compensate for this, the control coefficient α is made to swing around 0.9;
If it becomes thinner, the control coefficient α is allowed to swing around 1.1. As a result, the average value of the air-fuel ratio is made to match the stoichiometric air-fuel ratio again, and air-fuel ratio feedback control is obtained.

By the way, such air-fuel ratio deviations often occur due to changes in engine operating conditions.
As a result, in the O ₂ feedback control described above,
When the engine operating condition is in a certain range,
The control coefficient α is in a state where it fluctuates around 1.1, but in other areas it starts to fluctuate around 0.9. When the operating condition of the engine changes, the control coefficient α may also change.

However, such feedback control inevitably involves a control delay time, and as a result, as described above, the engine operating state shifts from one region to another, causing the air-fuel ratio to deviate from the logical value. Even if feedback is applied to correct it, it will take some time before the above control coefficient α shifts from the value corresponding to one region to the value corresponding to the new region and returns the air-fuel ratio to the theoretical value. During this time, the engine is operated with the air-fuel ratio deviating from the theoretical value.

Therefore, in order to eliminate this difficulty, the operating state of the engine is divided into many regions according to the load size, rotation speed, etc., and for each region, the standard value of the control coefficient α (α = 1.0 ) and store it in non-destructive memory.
Thereafter, by performing control using the deviation each time the same operating region is entered, the control coefficient α is always maintained.
This makes it possible to control even when it is swinging around 1.0.

Drive signal P _i for injector 4 at this time
The pulse width T _i of is determined by the following equation (2).

T _i : {K ₁・Q _A /N・K ₂・α・(1.0−K _l )} +T _S ……(2) Here, K _l is the reference value of the control coefficient α at that time
The deviation value from 1.0 is expressed as the following equation (3).

K _l = α−1.0 ...(3) In the engine control system using this learning control method, the above deviation data K _l is sequentially backed up from the power supply by learning while the engine is running.
It is designed to replenish or rewrite sections in a map of non-destructive memory such as RAM.

According to this learning control method, there is no need to first write and prepare each independent deviation data K _l in memory, and even if the characteristics of the engine or various control actuators change, Since the deviation data _Kl is self-corrected accordingly, correct control can always be expected, and the engine control state can be maintained correctly even in transient states.

However, certain conditions are set for writing the above-mentioned deviation value data in this learning control method. Writing is performed only when . This is a necessary requirement for proper control using correct data, and it is almost impossible to eliminate this condition.

Therefore, in this learning control system, the deviation value data corresponding to the operating region of the engine that only appears transiently or rarely appears in the actual operating state is No matter how much time passes, no new deviation value data will be written into the memory map, and the initially set data will remain as it is. As a result, as shown in Figure 3, the deviation value data The control coefficient α is changed when moving from operating area section A for which writing and storage has been completed to section B for which storage has not yet been completed, or when moving from this section B to section C for which storage has been completed. This has the drawback of causing a delay in the transition, during which the control is kept in an inappropriate state, causing the air-fuel ratio to deviate from the stoichiometric value, worsening exhaust gases, and causing knocking, which has an adverse effect on the engine.

[Purpose of the invention]

An object of the present invention is to eliminate such drawbacks of the prior art, and to provide an engine control system using a learning control method, in which almost no unstored area remains in the memory map, and appropriate control can be performed at all times. The aim is to provide a new engine control system.

[Summary of the invention]

In order to achieve this object, the present invention provides a learning control system in which when the number of data write sections for all memory area sections storing control data reaches a predetermined value, remaining data is not yet written. This is characterized in that the data in the writing completion section in the vicinity of the section is written to the section, and this is shown in the block diagram in accordance with the invention described in the claims column. The diagram is shown in Fig. 7.

[Embodiments of the invention]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An electronic internal combustion engine control device according to the present invention will be described in detail below with reference to embodiments of the drawings.

In one embodiment of the present invention, the configuration of the main parts is the same as the conventional learning control system shown in FIG. The only point is that it is configured to be executed by the microcomputer included in the circuit 3.

The process shown in FIG. 4 is periodically executed with sufficient frequency to appropriately control the injector 4. When this process starts, step S1 (hereinafter referred to as step S1) is executed. (omitted and simply written as S1, S2...) and S2 to find the intake air amount Q _A and rotational speed N of the engine, and then
In S3, data T _P is calculated from these data Q _A and N. Note that this data T _P is used as a parameter for dividing the operating state of the engine into regions.

Next, in S4, the signal O ₂ is acquired from the O ₂ sensor 5,
In the following S5 and S7, this signal O ₂ is sequentially checked, and in S5, it is determined whether the signal O ₂ has changed from rich to lean.
In other words, it is determined whether point P in Figure 2 _{is 1} or not, and the result is
If YES, the value of α at this time is stored as α _nio through S6, and then it goes to S9. If it becomes NO, it checks whether the signal _O2 has changed from lean to rich in S7, that is, as shown in Figure 2. Determine whether point P ₂ or not,
If the result is YES, α at this time is passed through S8.
After storing the value of as α _nax , proceed to S9. Then, when the results of S5 and S7 are both NO, that is, the value of α is determined to be between the maximum value α _nax and the minimum value α _nio in FIG. 4, and the processing according to this _flow is completed.

Now, if the result is YES in either S5 or S7 and you proceed to S9, in this S9 the average value of α α _neao
is calculated, and then in S10 it is determined from the data T _P and N which category the engine operating state is in at that time, and this category is set as A.

Next, in S11, the number of section A that was just determined in S10 is compared with the number A _OLD of section A that was determined in the process of S10 one time before and stored in the process of S14 (described later). , if they match, the process goes to S12 and a prepared counter is incremented, and if they do not match, the process goes to S13 and clears this counter.

After that, A _OLD of the data A mentioned above is passed through S14.
After the storage is performed, the process proceeds to S15, where the count value of the above-mentioned counter is checked and it is determined whether or not it is 3 or more. If the result in S15 is NO, the process directly advances to S24 and subsequent S28.

On the other hand, if the result in S15 is YES, proceed to S16, obtain data K _l using the data α _neao calculated in S9, and store this data K _l in section A of non-destructive memory such as power backup RAM. Write.

Here, the meaning of the result of S15 being YES will be explained.

First, in order for the result in S15 to be YES, the result in S11 must be YES at least three times in a row.
must become. This means that the processes up to S11 have been performed three or more times in a row when the engine operating state is in the same region classification.

On the other hand, the processing up to S11 is performed as follows:
When the result is YES in either S5 or S7,
In other words, the engine control using the control coefficient α is the second
This is when the test was carried out exactly at point _P1 or point _P2 in the figure.

Therefore, the result of S15 is YES because
This means that the engine feedback control based on the fluctuation of the control coefficient α shown in FIG. 2 was performed at least three times in a row while the engine operating state remained in the same range.

By the way, if the result in S15 becomes YES, the process in S16 is performed, so in the end, in this embodiment, the learning data writing conditions in the learning control method are such that the engine is kept in the same operating state region. It can be seen that the condition is satisfied by performing the feedback control based on the fluctuation of the control coefficient α shown in FIG. 2 at least three times. Note that when this write condition is satisfied may be arbitrarily determined as necessary.

After completing the process in S16, the process proceeds to S17, where the number of sections in the map of the memory to which data has been written by the process in S16 is checked, and this number is set as C. In order to do this, before starting the operation of this system, write "0" to all sections in the above memory map, and then
It is also possible to sequentially read out all the sections of this map in the process of , count the number of sections for which "0" has not been read out, and use it as C above. Configure a soft counter using the memory area, increment this soft counter every time the process of S16 is performed, and store the data of this counter.
The above C may be obtained by checking in S17.

Once C is obtained in this way, it is compared with a predetermined number, for example 25, in the next step S18, and it is determined whether or not C is 25 or more. While the result is NO, the process proceeds to S24 and subsequent steps, and the processes of S19 to S23 are skipped.

On the other hand, if the result in S18 is YES, that is, the memory
When it is determined that data has been written by learning to 25 of all the sections of the map, first, in S19, the section number x is set to 1.
Make it.

Here, an example of the memory map in this embodiment is shown in FIG.

In the example shown in FIG. 5, the memory map is divided into 8 sections in the row direction and 8 in the column direction, creating 64 divisions.At this time, the row direction is divided by a variable T _P representing the engine load. , the column direction is divided by the engine rotation speed N. Then, the division number x is numbered 0 in the first row and first column, and
They are determined sequentially from the column direction to the row direction so that the column is numbered 63. Note that this division number x is written in a part of each division with a bracket.

In S20, data is read from the section of the memory map whose number is x, and it is determined whether or not it is "0". Then, while the result is NO, the next S21 is skipped, and only when the result is YES, S21 is executed, data is read from the map section with section number (x-1), and it is placed in the section x. Write.

In S22, the division number x is incremented, that is, x is sequentially increased by 1, and the process continues.
In S23, this incremented partition number x is checked to determine whether it is less than or equal to 63, which is the total number of partitions in the memory map.
Return to , and repeat the processing of S20 to S22.

As a result, by the time data has been written to a predetermined proportion of all the sections of the memory map, that is, 25 out of 64 sections in this embodiment, data has already been written. Data is written to the sections that have not yet been written based on the data of the completed sections, and data that approximates the learning result is written to most sections of the memory map as shown in Figure 6. It will be completed as follows.

The processing from S24 to S28 is necessary for controlling the injector 4. First, in S24, data _Kl is read from section A of the memory map. Classification A at this time is determined in S10 or S29 and represents the current engine operating state range. In the following S25 and S26, the coefficients K ₂ and T _S are calculated in sequence, and then the process proceeds to S27, where the pulse width required for the drive signal P _i of the injector 4 is calculated from the control coefficient α, data K _l , variable T _P , etc. Data T _i representing this is calculated and set in a predetermined injector control register in the next process of S28, and the process according to this flow ends.

Therefore, according to this embodiment, the injector 4
control can be performed with good responsiveness using a learning control method, and when the data written to the memory map reaches a predetermined number of sections, approximate data can be written to most of the remaining sections. Therefore, it is possible to effectively eliminate delays in air-fuel ratio control due to the existence of sections for which data has not been written, and to sufficiently prevent deterioration of the exhaust gas condition.

By the way, in the above embodiment, the number of sections in the memory map, that is, the number of engine operating state area sections for control, is set to 64, and when the number of sections in which learning control data is written to this section reaches 25, the remaining sections are Approximate data is also written in the sections, but the number of sections at this time can be set arbitrarily, not limited to 64, and the number of sections mentioned above, 25, can also be set arbitrarily. Needless to say.

Also, regarding the method of writing approximate data at this time, in the above embodiment, the approximate data to be written to each unfinished data writing section is transferred to a section with a smaller number than the number of that section by the processing of S18 to S23. Going backwards, when the first section where learning control data is written is reached, the data is set to that section.
The present invention is not limited to this, and can be implemented. For example, for a write-unfinished section that exists between two sections in which learning control data has been written, data that is the average of the data of these two sections is Furthermore, this data may be averaged both in the column direction and in the row direction.

Although the above embodiment describes an example in which the present invention is applied to an air-fuel ratio control system, the present invention is not limited to this, and can be applied to any control system as long as it is a learning control system. Needless to say, the present invention may be applied to, for example, a knock control system.

Furthermore, in the above embodiment, writing of the approximate data to the unwritten sections of the memory map is performed for the first time after the control system to which this invention is applied starts operating, and the learning control data is written to a predetermined number of sections of the memory map. However, the present invention is not limited to this.
For example, after the above approximate data is written, the memory map sections are further rewritten using learning control data, and when the number of rewritten sections reaches a predetermined number, the above approximate data is written again. The same operation as above may be performed, and approximate data may be rewritten for the unrewritten data section.

For this purpose, for example, S17 in Fig. 4b
The soft counter described in 1 may be cleared following the process of S23.

〔Effect of the invention〕

As explained above, according to the present invention, memory and
Since it is possible to minimize the occurrence of unfinished data writing sections in the map, it is possible to eliminate the shortcomings of the conventional technology, to always sufficiently compensate for delays caused by feedback control, and to ensure adequate control even in transient conditions. Thus, it is possible to easily provide an electronic internal combustion engine control device that can maintain a good exhaust gas condition at all times.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing an example of an engine control system using the learning control method, Fig. 2 is a time chart for explaining the feedback control operation in the air-fuel ratio control system, and Fig. 3 is the same operation when changing the region classification. 4a and 4b are flowcharts illustrating the operation of an embodiment of the electronic internal combustion engine control device according to the present invention, and FIGS. 5 and 6 are conceptual diagrams of memory maps. , FIG. 7 is a block diagram showing an example of the basic configuration of the present invention. 1...Engine, 2...Intake air flow rate sensor,
3... Control circuit, 4... Injector, 5...
_O2 sensor.

Claims (1)

[Claims] 1 detection means for detecting the operating state of the engine;
A storage means having a plurality of storage sections for storing a state control amount used to control the engine, and a control value used for controlling the engine based on at least the state control amount stored in the storage means. A control device for an internal combustion engine comprising a calculation means for calculating the control value and a control means for controlling the engine based on the control value, which calculates a state control amount to be stored in the storage means based on the operating state of the engine. storage value calculation means; storage classification determination means for determining a storage classification of the storage means; and writing the state control amount calculated by the storage value calculation means into the storage classification of the storage means determined by the storage classification means. a first writing means; a counting means for calculating the number of write sections of the state control amount for the storage section of the storage means; and output upon detecting that the number of write sections calculated by the counting means exceeds a predetermined value. and a second comparator for writing a correction value calculated from the state control amount stored in the write completion section of the storage means into the write incomplete section of the storage means based on the output of the comparison means. What is claimed is: 1. An electronic internal combustion engine control device comprising: writing means.