JPS62191641A - Learning control device for air-fuel ratio for internal combustion engine - Google Patents

Abstract

PURPOSE:To improve the responsiveness of control by operating and renewing a learning correction factor and a learning correction quantity in this time operating zone based on deviation between another operating zone having an equal intake air flow rate and the injection quantity, basic injection quantity, and feedback correction factor in this time. CONSTITUTION:Whether the operating zones in the last time and in this time are the same operating zones or not is judged by a judging means N and, when judged yes, a first injection quantity is operated by a first injection quantity operating means O. When judged no, on the other hand, an injection quantity corresponding to the deviation and operating condition from the basic injection quantity and the reference value of the air-fuel ratio feedback correction factor in another operating zone having an equal intake air flow rate to that of the operating zone in this time, is retrieved by a first retrieving means P. Also, an injection quantity in the operating zone in this time is retrieved by a second retrieving means Q. And, based on the outputs of these retrieving means P, Q, a learning correction factor and a learning correction quantity in the operating zone in this time are operated by a correction operating means R and, according to these operated results, a second injection quantity is operated by an operating means T.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a learning control device for an air-fuel ratio feedback control system in an internal combustion engine having an electronically controlled fuel injection device.

<Prior Art> A fuel injection valve used in an electronically controlled fuel injection system is opened by a drive pulse signal given in synchronization with engine rotation, and during that time, fuel at a predetermined pressure is injected throughout the valve plate. ing. Therefore, the fuel injection amount is controlled by the pulse width of the drive pulse signal, and if this pulse width is set as Ti and the control signal corresponds to the fuel injection amount, then in order to obtain the stoichiometric air-fuel ratio, which is the target air-fuel ratio, Ti is determined by the following formula. determined by.

Tj=Tp−COEF・α+Ts However, 'rp is a basic pulse width corresponding to the basic injection amount, and is called the basic injection amount for convenience. Tp=-Q/N, where K is a constant, Q is the engine intake air flow rate, and N is the engine speed. C0
EF is various correction coefficients such as water temperature correction. α is an air-fuel ratio feedback correction coefficient for air-fuel ratio feedback control (λ control) to be described later. Ts is the voltage correction amount and the F/I opening/closing valve delay correction amount, which is used to correct the injection flow rate deviation due to the change in the injection flow rate of the fuel injector due to battery voltage fluctuation and the response delay of the F/I to the fuel injection pulse. It is something.

Regarding λ control, an O2 sensor is installed in the exhaust system to detect the actual air-fuel ratio, and the slice level controls whether the air-fuel ratio is richer or leaner than the theoretical air-fuel ratio.
For this reason, the aforementioned air-fuel ratio feedback correction coefficient α is determined, and by changing this α, the stoichiometric air-fuel ratio is maintained.

Here, the air-fuel ratio feedback correction coefficient αΦ value is changed by proportional-integral (PI) control to achieve stable control.

That is, the output voltage of the 02 sensor is compared with the slice level voltage, and if it is higher or lower than the slice level, the air-fuel ratio is rich (without suddenly enriching or thinning the air-fuel ratio). If it is thin), first lower (raise) it by P, then gradually lower (raise) it one minute at a time.
Then, the air-fuel ratio is controlled to be Fl<(rich<).

However, under conditions where λ control is not performed, α is clamped and a desired air-fuel ratio is obtained by setting various correction coefficients COEF.

By the way, if the base air-fuel ratio under λ control conditions, that is, the air-fuel ratio when α = 1, could be set to the stoichiometric air-fuel ratio (λ = 1), foot control would not be necessary. This includes fluctuations and aging of component parts (e.g. air flow meter, fuel injection valve, pre-noise regulator control unit), non-linearity of the pulse width-flow rate characteristic of the fuel injection valve, changes in operating conditions and environment, etc. Because of these factors, the base air-fuel ratio deviates from λ=1, so feedback control is performed.

However, if the base air-fuel ratio deviates from λ=1, it takes time to stabilize the level difference in the base air-fuel ratio to λ=1 by feed pack control when the operating range changes significantly. And for this the proportionality and integral constants (
P/1 minute) is increased, resulting in overshoot or undershoot, resulting in poor controllability. In other words, if the base air-fuel ratio deviates from t-1, the air-fuel ratio will be controlled within a range that deviates considerably from the stoichiometric air-fuel ratio.

(As a result, the three-way catalyst is operated at a point where the conversion efficiency is poor, and in addition to the costa knob due to the increase in the amount of precious metals in the catalyst, the conversion efficiency further deteriorates due to deterioration of the catalyst, forcing the catalyst to be replaced. be done.

Therefore, by setting the base air-fuel ratio to λ = 1 through learning, it is possible to eliminate the deviation from λ-1 caused by the step in the base air-fuel ratio, and to reduce the P/I component, thereby improving controllability. An air-fuel ratio learning control device designed to achieve this purpose has been proposed by the applicant in Japanese Patent Application No. 58-76221 (Japanese Unexamined Patent Publication No. 59-20
No. 3828) or Japanese Patent Application No. 511197499.

This is because if the base air-fuel ratio deviates from the stoichiometric air-fuel ratio during air-fuel ratio feedback control, the air-fuel ratio feedback correction coefficient α becomes large to compensate for the gap.
Find out the engine operating state and α at this time, and create a learning correction coefficient based on α! is determined and memorized, and when the same engine operating condition returns, the base air-fuel ratio is corrected by adding 1 to the stored learning correction coefficient so that the base air-fuel ratio is more responsive to the stoichiometric air-fuel ratio. The learning correction coefficient here! The storage is performed for each region in a predetermined range obtained by dividing the map in the RAM into a grid according to appropriate parameters of the engine operating state such as engine speed and load.

Specifically, a map of learning correction coefficients KA corresponding to engine operating conditions such as engine speed and load is provided in RAM, and when calculating the fuel injection amount Ti, the basic injection oil T is calculated as shown in the following formula.
Let p be the learning correction coefficient! ! Correct with.

T i =Tp−COEF・Kl・α+Ts and K
Study A will proceed in the following steps.

i) Detect the region of the engine operating state at that time in the steady state, and calculate the deviation Δα of α from the base value α1 during that period.
(−α−α,) is detected as the average value. The base value α is generally set to 1 as a value corresponding to λ-1.

ii) Searching for Kl that has been learned up to now corresponding to the region of the engine operating state.

1ii) Find the value of K124M·Δα from K/ and Δα, and use the result (learning value) as a new K It ts+ to update 4.a. M is a constant and O<M<1.

By the way, in such a conventional learning method for air-fuel ratio feedback control, the deviation Δα cannot be detected accurately unless it is in a steady state, so learning is performed by detecting Δα only in a steady state. During transient operating conditions,
Learning is not performed in operating areas where the vehicle is operated only temporarily.

For this reason, there are areas where the learning progress is large (hereinafter referred to as learning areas) and other areas where the learning progress is small (hereinafter referred to as unlearning areas). If the operating condition changes in this state, if a deviation occurs in the air-fuel ratio in the system, α and the air-fuel ratio λ will change between the learning region and the unlearning chain acid.
As a result, there is a difference in the air-fuel ratio λ when moving between the learned area and the unlearned area, leading to deterioration of exhaust emission characteristics and fuel efficiency in transient operating conditions, The effect of learning does not increase.

In view of this, the applicant of this application detects the degree of learning progress, and uses the learning correction coefficient learned in the driving region where the learning progress is large to have a convex value of 6, and calculates the learning progress where the intake air flow rate Q is equal to that of the driving region. A patent application filed in 1984 provides an air-fuel ratio tli constant learning control device that improves the reliability of learned values and improves air-fuel ratio control accuracy by performing learning in small operating ranges.
The application was filed as No. 009446.

<Problems to be Solved by the Invention> As shown in FIG. 7, as the fuel injection amount Ti increases, the influence of deterioration of the fuel injection valve decreases.

Therefore, in the former learning control device, when the temperature is completely warm,
If the control is performed to correct the effect of the deterioration of the fuel injector, the fuel injection amount Tt will increase by the water temperature increase correction 1 when the engine is cold and the increase correction after starting, so the effect of the deterioration of the fuel injector will be reduced when the engine is completely warmed up. Actual fuel injection amount Ti
In the latter estimation learning control device η, the learning correction coefficient K learned in the driving region where the learning progress is large.
Based on l, learning is performed in a small operating area where the learning progress is small and the intake air flow rate Q is equal to the relevant operating area, but in these two operating areas, the fuel injection lT
Since i was different, it was not possible to accurately calculate the fuel injection amount Ti, which was also affected by the deterioration of the fuel injector.

The present invention was made in view of the above-mentioned circumstances, and it is possible to accurately calculate the fuel injection amount and improve air-fuel ratio control accuracy even in operating ranges where the fuel injection amount is different and the influence of fuel injector deterioration is different. An object of the present invention is to provide an air-fuel ratio learning control device for an internal combustion engine.

Means for Solving the Problems> Therefore, as shown in FIG. 1, the present invention provides a basic injection amount setting means A that sets the basic injection amount based on the engine operating state.
, a rewritable basic injection amount storage means B for storing the basic injection amount, a basic injection amount updating means C for updating the data of the basic injection amount storage means to the set basic injection amount, and an air supply system provided in the exhaust system. an air-fuel ratio feedback correction coefficient setting means E that compares the actual air-fuel ratio detected by the fuel ratio detection means with a target air-fuel ratio and sets an air-fuel ratio feedback correction coefficient so as to bring the actual air-fuel ratio closer to the target air-fuel ratio; a rewritable learning correction coefficient storage means F that stores a learning correction coefficient to be multiplied by the basic injection amount for each subdivided operating region; a learning correction coefficient search means G that searches for a learning correction coefficient; and a rewritable learning correction that stores a learning correction amount to be added to a value obtained by multiplying the basic injection amount by a learning correction coefficient for each subdivided driving region. a quantity storage means H, and a basis of the feedback correction coefficient stored in the learning correction coefficient storage means based on the actual operating condition. 1 Rewritable j5 soC deviation record 4 that stores the deviation from the east value for each subdivided operating region
．． α means J; injection amount storage means for storing the injection amount corresponding to the operating state for each subdivided operating region; and deviation calculation means for calculating the deviation from the set feedback correction coefficient. a deviation updating means M for updating the data of the same engine operating range in the deviation storage means based on the deviation determined by the deviation; and an operating state for determining whether the previous operating range and the current operating range are the same operating range based on the actual operating state. determining means N; when it is determined that the operating range is the same, an air-fuel ratio feedback correction coefficient and learning correction updating means add the learning correction amount to the value multiplied by the basic injection amount to the set basic injection amount; a first injection amount calculation means 0 that calculates a first injection amount based on a first injection amount calculation means 0; , a first search means P that searches for the deviation and the injection amount; a second search means Q that searches for the injection amount in the current operation region when it is determined that the previous and current operation regions are different; and the other operation. Calculate the learning correction coefficient and learning correction amount in the current operating region based on the basic injection amount, deviation, and injection amount in the region, the injection amount in the current operating region, the set basic injection amount, and the calculated deviation. Correction calculation means R
and a correction updating means S for updating the data of the same operating region in the learning correction coefficient and learning correction meter storage means to the calculated learning correction coefficient and learning correction amount, and the air-fuel ratio feed set to the basic injection amount. a learning correction updating means that calculates the hack correction coefficient; and a second unit that calculates a second injection amount by adding the air-fuel ratio feedback correction amount multiplied by the basic injection amount.
an injection amount calculation means T; and a drive pulse signal output means for outputting a drive pulse signal corresponding to the calculated second injection amount or the first injection amount calculated by the first injection amount calculation means to the fuel injection valve U. Equipped with W and .

In this way, when the operating region changes, the learning correction coefficient and learning correction amount for the current operating region are adjusted between the current operating region and other operating regions where the intake air flow rate is the same as the current operating region. Set based on deviation, etc.

<Example> An embodiment of the present invention will be described below.

In FIG. 2, the engine 1 includes an air cleaner 2°, an intake duct 3. Throttle chamber 4 and intake manifold 5
Air is inhaled through.

An air flow meter 6 is provided in the intake duct 3 and outputs a voltage signal corresponding to the intake air flow IQ times signal.

The throttle chamber 4 includes a primary throttle valve 7 and a secondary throttle valve 8 that operate in conjunction with an accelerator pedal (not shown).
is provided to control the intake air flow jlQ. Further, an auxiliary air passage 9 is provided that bypasses these throttle valves 7 and 8, and an idle control valve 10 is interposed in this auxiliary air passage 9. A fuel injection valve 11 is provided in the intake manifold 5 or the intake boat of the engine 1 . This fuel injection valve 11 is an electromagnetic fuel injection valve that opens when a solenoid is energized, and then closes when the energization is stopped and closes.The fuel injection valve 11 is an electromagnetic fuel injection valve that is energized by a solenoid to open the valve, and then is stopped and closed by energizing the solenoid in response to a drive pulse signal. The fuel, which is controlled to a predetermined pressure by
Supply injection to.

From engine 1, exhaust manifold 12. Exhaust duct 13
．． Exhaust gas is discharged via the three-way catalyst 14 and the muffler 15.

The exhaust manifold 12 is provided with an OT sensor 16. This 0□ sensor 16 is the oxygen concentration in the atmosphere (constant)
outputs a voltage signal according to the ratio of the oxygen concentration in the exhaust gas and
This is a known sensor whose electromotive force changes suddenly when the air-fuel mixture is combusted at the stoichiometric air-fuel ratio. Therefore, the 02 sensor I6 is a means for detecting the air-fuel ratio (rich/lean) of the air-fuel mixture. The three-way catalyst 14 is a catalytic device that efficiently oxidizes or reduces Co, HC, and NOx in the exhaust components near the stoichiometric air-fuel ratio of the air-fuel mixture and converts them into other harmless substances.

In addition, a crank angle sensor 17 is provided.

In the crank angle sensor 17, a signal disk plate 19 is provided on the crank pulley 18, and teeth provided on the outer circumference of the plate 19 output a reference signal every 120 degrees and a position signal every 1 degree, for example. Here, the engine speed N can be calculated by measuring the period of the reference signal.

The air flow meter 6, crank angle sensors 17 and 0
The output signals from the two sensors 16 are both input to the control unit 30. Furthermore, control unit 3
The voltage of a battery 20 is directly applied to the engine 0 via an engine key switch 21 as its operating power source and for detecting the power supply voltage.

Furthermore, the control unit 30 is provided with a water temperature sensor 22 for detecting the engine cooling water temperature as required. - Throttle sensor 23 including an idle switch that detects the throttle opening of the next throttle valve 7. Vehicle speed sensor 24 that detects vehicle speed. A signal from a neutral switch 25 or the like that detects the neutral position of the transmission is input. Then, the control unit 30 performs arithmetic processing based on various human input signals, outputs a drive pulse signal with an optimal pulse width to the fuel injection valve 11, and obtains the fuel injection amount for obtaining the optimal air-fuel ratio.

The control unit 30, as shown in FIG.
PLJ31. P-ROM32. It has an address decoder 34 on the CMO5-RAM 33. Here, the RAM 33 is a rewritable storage means for learning control, and this RA
The operating power source for M33 is the engine key switch 21.
In order to retain the memory contents even after the engine is turned off, the battery 20 is connected not through the engine key switch 21 but through a suitable stabilized power source.

Among the input signals to the CPU 31, the air flow meter 6.
0□Sensor 16. Battery 20. Since each voltage signal from the water temperature sensor 22 and the throttle sensor 23 is an analog signal, the analog human power interface 35 and the A
The signal is input via a /D converter 36.

The A/D converter 36 is controlled by the CPU 31 via an address decoder 34 and an A/D conversion timing controller 37. The reference signal and position signal from the crank angle sensor 17 are inputted via a one-way multi-circuit. A signal from the idle switch in the throttle sensor 23 and a signal from the neutral switch 25 are inputted via a digital human power interface 39, and a signal from the vehicle speed sensor 24 is inputted via a waveform shaping circuit 40. ing.

The output signal (driving pulse signal for the fuel injection valve 11) from the cPU 31 is sent to the fuel injection valve 11 via the current waveform control circuit 4L.

Here, the CPU 31 performs input/output operations, arithmetic processing, etc. according to a program (stored in the ROM 32) based on the flowchart (fuel injection amount calculation routine) shown in FIG. 4, and controls the fuel injection amount.

Incidentally, the functions of each means described in the above <Means for solving the problems> are achieved by the above program.

Next, the operation will be explained with reference to the flowchart shown in FIG.

At Sl, various signals such as intake air flow rate Q1 and engine speed N are read. In step 2, basic injection 1Tp (=K - Q/N) is calculated from the intake airflow iQ obtained from the signal from the air flow meter 6 and the engine rotation speed N obtained from the signal from the crank angle sensor 17. This part corresponds to the basic injection amount calculation means.

In S3, the calculated basic injection amount Tp is stored in the RAM 33.
to be memorized. Therefore, the RAM 33 corresponds to basic injection amount storage means, and this part corresponds to basic injection amount updating means.

In S4, various correction coefficients C0EF are set as necessary,
In S5, the various correction coefficients C0EF that have been set are stored in the RAM33.
to be memorized.

In S6, the output from the Oz sensor 16 is compared with the slice level, and the air-fuel ratio feedback correction coefficient α is set by proportional-integral control so that the actual air-fuel ratio approaches the stoichiometric air-fuel ratio λ-1. Therefore, the portion .'- corresponds to the air-fuel ratio feedback coefficient setting means.

In S7, the average deviation value τi is calculated from the reference value α1 of the feedback correction coefficient α. Therefore, this portion corresponds to the deviation calculation means.

Specifically, as shown in FIG. 5, the deviation Δα (=α−α1) of the feedback correction coefficient α from the reference value α1 is
1. Let it be Δα2.

These upper and lower peak values Δα1. Deviation Δ based on Δα2
The average value n of α is calculated based on the following equation.

τ7=(Δα, +Δα2)/2 In S8, one average value is stored in the RAM 33.

Here, the average value τW is determined by dividing the map with the engine speed N on the horizontal axis and the basic injection ff1T'p on the vertical axis using a grid of about 8 x 8, dividing the operating range, and storing each operating range on the RAM 33. It is stored in each area. Therefore, the RAM 33 corresponds to a deviation storage means, and this portion corresponds to a deviation updating means.

In S9, the area number of the current operating range is read out from the map based on the engine speed N and the basic injection point 'rp' and stored.

In S10, it is determined whether the previous and current operating ranges are the same. Specifically, the area numbers of the previous driving range are successively retrieved, and the determination is made based on whether or not the area number of the previous driving range is the same as the area number of the current driving range. If YES, that is, the operating ranges of this time and the previous time are the same, the process advances to S14, and if No, that is, those operating ranges are different, Sll
Proceed to. Therefore, this portion corresponds to the driving state determining means.

In Sll, it is determined whether the previous and current operating regions are operating regions in which the intake air flow rate is equal, and if YES, that is, they are equal, the process advances to S14, and if No, the process advances to S] and 2. Here, the operating regions where the intake air flow rate is equal are the regions on the broken lines in the map shown in FIG.

In S12, the detected engine speed N and basic injection ff1
The learning correction coefficient X and the learning correction iY in the current driving range are retrieved from the RAM 33 under the same conditions as Tp: °14, therefore, this portion corresponds to the learning correction coefficient retrieval means and the learning correction amount storage means.

Here, the learning correction coefficient Y and the learning correction amount Z are calculated by partitioning a map with the engine speed N on the horizontal axis and the basic injection ff1Tp on the vertical axis using a grid of about 8 x 8, dividing the area into RA
It is stored on M33 for each operating region. Therefore, the RAM 33 corresponds to learning correction coefficient storage means and learning correction amount storage means.

In S13, the searched learning correction coefficient Y and learning correction amount Z
, the calculated basic injection amount Tp, various correction coefficients C0EF,
The injection amount Ti is calculated based on the following equation from the air-fuel ratio feedback correction coefficient α and the like.

Ti=C0EEFXαXYXTp +Ts +Z...
(1) Note that Ts is a voltage correction bone.

Therefore, this portion corresponds to the first injection amount calculation means. Here, the learning correction amount is for correcting the opening/closing delay of the fuel injection valve 11, and is added in order to set it to be substantially constant.

Further, the learning correction coefficient Y is used to correct an error in the intake air flow rate.

On the other hand, if the previous and current operating ranges have changed so that the intake air flow rate is the same, the process advances to S14.

To be more specific, let us take as an example the case where the operating region A in FIG. 6 changes to the operating region B adjacent to A.
14, the basic injection 'rp in the previous operating range, the average value of various correction coefficients COE F l + deviation 1-8. The injection amount Ti is retrieved from the RAM 33. Therefore, this portion corresponds to the first search means.

Further, the RAM 33 corresponds to an injection amount storage means.

In S15, the basic injection amount 'rp in the current operating range is
,, various correction coefficients COE F z, average value of deviation τ12
゜Injection i'ri is retrieved from the RAM 33. Therefore, this portion corresponds to the second search means.

In S16, a new learning correction coefficient Yw and a new learning correction amount ZN are calculated from the search values of the previous and current driving ranges based on the two-coupled equation 2 of the following equation.

Tl1(1-2zζ-n i-7--) = CO
E F' 1 X Y HX T p+
Ts 1 ZN ・・・・・・(2) T 1z (1--z) =CP EF2 XYN X
Tp+TS+Z, 4 (3) Therefore, this portion corresponds to the correction calculation means.

In S17, a new learning correction coefficient Y9. Learning correction amount ZH
The data for the current operating area will be updated. Therefore, this portion corresponds to the correction/update means.

At 318, a new learning correction coefficient YN, learning correction amount 2,
The injection lTi is calculated based on the above equation (1).

Therefore, this portion corresponds to the second injection amount calculation means.

In S19, data of the current operating range is updated to the calculated injection iTi.

In S20, the injection lTi or 5 determined in S14 is
A drive pulse signal having a pulse width of the injection amount Ti determined in step 18 is output at a predetermined timing in synchronization with the engine rotation, and is applied to the fuel injection valve 11 via the current waveform shaping circuit 41, and fuel injection is performed. It will be done.

Therefore, the current waveform shaping circuit 41) and the CPU 31
A drive pulse output means is configured.

As explained above, the learning correction coefficient Y for the current driving region
And the learning correction amount Z is the previous and current injection amount 'rtl, Ti
Since the calculation is performed based on the average value τtx , , m □ of the Zl deviation Δα, the average value T1.
The influence of deterioration can be corrected by τ12. In addition, since they are calculated based on the operating region where the intake air flow rate is equal, the learning correction coefficient Y can be set to a value that corresponds to the change in the fuel injection valve 11 over time. Similarly, control responsiveness can be improved. These results
It can improve starting performance, acceleration performance, and exhaust emissions.

<Effects of the Invention> As explained above, the present invention allows the learning correction coefficient and learning correction amount for the current operating region to be compared to other operating regions where the intake air flow rate is the same, the current injection amount, the basic injection amount, and the deviation. Since the system calculates and updates the fuel injection valve based on the changes over time, it is possible to improve control responsiveness regardless of changes in the fuel injection valve over time, while also correcting the effects of deterioration that changes in response to the injection amount, improving startability, acceleration, etc. I can figure it out.

[Brief explanation of drawings]

FIG. 1 is a diagram corresponding to claims of the present invention, FIG. 2 is a configuration diagram showing an embodiment of the present invention, FIG. 3 is a block circuit diagram of the control unit in FIG. 2, and FIG. 4 is a flowchart of the same as above. 5 and 6 are diagrams for explaining the same effect as above, and FIG. 7 is a diagram for explaining the conventional drawbacks.

Claims (1)

[Scope of Claims] Basic injection amount setting means for setting a basic injection amount based on engine operating conditions; rewritable basic injection amount storage means for storing the basic injection amount; A basic injection amount updating means for updating data in the amount storage means and an actual air-fuel ratio detected by an air-fuel ratio detection means provided in the exhaust system and a target air-fuel ratio are compared to bring the actual air-fuel ratio closer to the target air-fuel ratio. an air-fuel ratio feedback correction coefficient setting means for setting an air-fuel ratio feedback correction coefficient as shown in FIG. learning correction coefficient retrieval means for retrieving a learning correction coefficient of a corresponding region from the learning correction coefficient storage means based on the actual engine operating state; and learning correction added to the value obtained by multiplying the basic injection amount by the learning correction coefficient. a rewritable learning correction amount storage means for storing the amount for each subdivided driving region; a learning correction amount retrieval means for searching the learning correction amount storage means for a corresponding learning correction amount based on the actual driving condition; rewritable deviation storage means that stores the deviation of the feedback correction coefficient from the reference value for each subdivided operating region; and an injection amount coefficient that stores the injection amount corresponding to the operating state for each subdivided operating region. storage means; deviation calculation means for calculating the deviation from the set feedback correction coefficient; deviation updating means for updating data in the same engine operating range in the deviation storage means to the calculated deviation; an operating state determination means for determining whether or not the previous and current operating regions are the same operating region based on the state; and when it is determined that the operating regions are the same, the set basic injection amount is subjected to an air-fuel ratio feedback correction coefficient and a learning correction. a first injection amount calculation means that calculates a first injection amount by multiplying a coefficient and adding the learning correction amount to the multiplied value; a first search means for searching for the basic injection amount, deviation, and injection amount in another operating region where the intake air flow rate is equal to the operating region; a second search means for searching for the current injection amount based on the basic injection amount, deviation, and injection amount in the other operating region, and the injection amount in the current operating region, the set basic injection amount, and the calculated deviation; a correction calculating means for calculating a learning correction coefficient and a learning correction amount in the driving region; and updating data of the same driving region in the learning correction coefficient and learning correction amount storage means to the calculated learning correction coefficient and learning correction amount. a correction updating means, which multiplies the basic injection amount by the set air-fuel ratio feedback correction coefficient and the calculated learning correction coefficient, and adds the calculated learning correction amount to the multiplied value to perform a second injection; a second injection amount calculation means for calculating the amount; and a drive for outputting a drive pulse signal corresponding to the calculated second injection amount or the first injection amount calculated by the first injection amount calculation means to the fuel injection valve. An air-fuel ratio learning control device for an internal combustion engine, comprising: a pulse signal output means;