JPH01142238A - Air-fuel ratio feedback control device for electronic control fuel injection type internal combustion engine - Google Patents

Abstract

PURPOSE:To solve the air-fuel ratio dispersion between cylinders by providing an exhaust component detecting means on an exhaust passage assembly section assembled for each cylinder group and performing the air-fuel ratio feedback control based on the exhaust component detection value after the preset time elapses since the exhaust stroke if each cylinder. CONSTITUTION:An exhaust component detecting means B is provided on an exhaust passage assembly section assembled for each cylinder group consisting of multiple cylinders having at least no overlapped exhaust strokes, the output signal is inputted to an air-fuel ratio detecting means C for each cylinder. The exhaust component detection value after the preset time is specified as the exhaust component detection value of the preset cylinder in the cylinder group based on the exhaust stroke timing of each cylinder to detect the air-fuel ratio for each cylinder. The detected air-fuel ratio and the target air-fuel ratio are compared for each cylinder by a feedback correction value setting means E, the feedback correction value is set in response to the deviation, the basic fuel injection quantity is corrected by a fuel injection quantity setting means F based on this correction value to control a fuel injection means H.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to an air-fuel ratio feedback control device for an electronically controlled fuel injection type internal combustion engine. The present invention relates to a system that detects the air-fuel ratio and performs feedback correction control on the fuel injection amount so as to bring the actual air-fuel ratio closer to the target air-fuel ratio.

<Prior Art> Conventionally, an electronically controlled fuel injection type internal combustion engine equipped with this type of air-fuel ratio feedback control device is disclosed in Japanese Patent Application Laid-Open No. 60-2
There are some such as those shown in Publication No. 40840 and the like.

To explain this, the basic fuel injection amount Tp (=KxQ/N; K is a constant), and further calculates various correction coefficients COEF according to engine operating conditions such as engine temperature, air-fuel ratio feedback correction coefficient LAMBDA, and changes in the effective valve opening time of the electromagnetic fuel injection valve due to battery voltage. The correction numerator s for correction is calculated respectively, and based on these, the basic fuel injection ff
1Tp is corrected and the final fuel injection amount Ti (=Tp
Set

Note that the various correction coefficients C0EF are, for example, C0EF=
1 Kxt+Ktw+KAs+KA++...where K)1+1 is the air-fuel ratio correction coefficient, KTW is the water temperature increase correction coefficient, KA3 is the starting and post-start increase correction coefficient, and KAI is the after-idling increase This is a correction coefficient.

Then, by outputting the drive pulse signal in the pulse corresponding to the fuel injection amount Ti thus set to the electromagnetic fuel injection valve provided for each cylinder at a predetermined timing, a predetermined amount of fuel is supplied to the engine. It was intended to be supplied by injection.

The air-fuel ratio feedback correction coefficient LAMBDA is for controlling the air-fuel ratio of the intake air-fuel mixture of the engine to a target air-fuel ratio (for example, the stoichiometric air-fuel ratio), and the value of the air-fuel ratio feedback correction coefficient LAMBDA is proportional to integral. It is changed by control to ensure stable control.

In other words, as shown in Fig. 8, when the air-fuel mixture is combusted at the stoichiometric air-fuel ratio, the electromotive force changes suddenly depending on the oxygen concentration ratio in the exhaust gas, and the electromotive force is high on the rich air-fuel mixture side and low on the lean air-fuel mixture side. Oxygen sensor with low electromotive force (Utility Model No. 61-18284)
No. 6, etc.) 20 is provided at the part where the exhaust passages of each cylinder of the engine 21 are gathered (the collection part of the exhaust manifold 22), and the output voltage from the oxygen sensor 20 and the reference voltage (corresponding to the stoichiometric air-fuel ratio) are slice level) to determine whether the air-fuel ratio of the engine intake mixture (air-fuel ratio of all cylinders) is rich or lean with respect to the stoichiometric air-fuel ratio. For example, if the air-fuel ratio is lean (rich), , the air-fuel ratio feedback correction coefficient LAMBD^ is gradually increased (decreased) by a predetermined integral (1 minute), and the air-fuel ratio is controlled to the stoichiometric air-fuel ratio by increasing (decreasing) the fuel injection (jiTi). .still,
When the air-fuel ratio is reversed from rich to lean, the air-fuel ratio feedback correction coefficient LAMBDA is changed by a proportional amount (P) larger than the integral (1 minute) to improve control responsiveness.

In FIG. 8, 23 is an air cleaner, 24 is a throttle valve, 25 is an intake manifold, 26 is a three-way catalyst, 27
is a muffler.

<Problems to be Solved by the Invention> By the way, the above-mentioned oxygen 0□ sensor is installed at the gathering part of the exhaust passages (exhaust manifolds) of all cylinders or partial cylinders of the engine (for example, one bank each in a type 8-cylinder engine). However, the engine does not detect the oxygen concentration ratio in the exhaust gas separately for each cylinder. Since there are multiple factors that cause air-fuel ratio variations between cylinders, when performing air-fuel ratio feedback control for all cylinders or partial cylinders using the oxygen sensor described above, the air-fuel ratio of each cylinder can be adjusted individually to the target air-fuel ratio. Since the fuel ratio cannot be controlled and fluctuations in the air-fuel ratio cannot be sufficiently suppressed, the exhaust properties are inconsistent, and the ability of the three-way catalyst to purify the exhaust must be set large. There is a problem in that the amount of precious metal used in the base catalyst increases, leading to an increase in cost.

Factors that cause air-fuel ratio variations among the cylinders mentioned above include uneven intake air distribution, variations in fuel injection valve characteristics, and differences in cylinder filling efficiency, which cause rich/lean air-fuel ratios in each cylinder. However, with conventional air-fuel ratio feedback control, the air-fuel ratio cannot be detected for each cylinder. The air-fuel ratio was supposed to fluctuate around .

Such air-fuel ratio variations between cylinders can be resolved by detecting the air-fuel ratio of each cylinder independently and performing air-fuel ratio feedback control for each cylinder, but in order to detect the air-fuel ratio for each cylinder, If an oxygen sensor is provided for each cylinder, there is a problem in that the cost increases too much.

The present invention has been made in view of the above problems, and it is an object of the present invention to enable air-fuel ratio feedback control to be performed for each cylinder without causing a significant increase in cost.

<Means for Solving the Problems> Therefore, in order to achieve the above object, the present invention, as shown in FIG. Configure the feedback control device.

(A) Engine operating state detection means for detecting an engine operating state that includes at least a parameter related to the amount of air taken into the engine. (B) Exhaust gas collected for each cylinder group consisting of a plurality of cylinders whose exhaust strokes do not overlap at least. Exhaust component detection means (C) which is installed in each passage gathering part and detects engine exhaust components; detects the exhaust stroke timing of each cylinder;
After a predetermined time from the exhaust stroke timing, the exhaust component detected by the exhaust acid detection means is specified as the exhaust component of a predetermined cylinder in the cylinder group, and the air-fuel ratio is detected for each cylinder based on the exhaust component. Cylinder-specific air-fuel ratio detection means (D) Basic fuel injection amount setting means for setting a basic fuel injection amount based on the engine operating state detected by the engine operating state detection means (E) The cylinder-specific air-fuel ratio detection means Feedback correction that compares the detected actual air-fuel ratio and the target air-fuel ratio for each cylinder and sets a feedback correction value for each cylinder to correct the basic fuel injection amount so that the actual air-fuel ratio approaches the target air-fuel ratio. Value setting means (F) Fuel injection amount setting means (G) for setting the fuel injection amount for each cylinder by correcting the basic fuel injection amount based on the feedback correction value set for each cylinder by the feedback correction value setting means. ) Drive pulse signal output means for outputting a drive pulse signal corresponding to the fuel injection amount for each cylinder set by the fuel injection amount setting means in correspondence with each of the fuel injection means (H) provided for each cylinder. 〉 According to the air-fuel ratio feedback control device having such a configuration,
When the engine operating state detecting means A detects the engine operating state including at least a parameter related to the amount of air taken into the engine, the basic fuel injection amount setting means sets the basic fuel injection amount based on this engine operating state. Set. The exhaust component detection means B is installed in each of the exhaust passage gathering portions that are gathered for each cylinder group consisting of a plurality of cylinders whose exhaust strokes do not overlap each other, and detects engine exhaust components.

Further, the cylinder-specific air-fuel ratio detecting means C detects the exhaust stroke timing of each cylinder, and after a predetermined time from the exhaust stroke timing, the exhaust components detected by the exhaust component detecting means are detected in the exhaust stroke timing of the predetermined cylinder in the cylinder group. Specifically, the air-fuel ratio is detected for each cylinder based on the exhaust component.

Then, the feedback correction value setting means E compares the actual air-fuel ratio detected by the cylinder-specific air-fuel ratio detection means C with the target air-fuel ratio for each cylinder, and the actual air-fuel ratio of each cylinder approaches the target air-fuel ratio. A feedback correction value for correcting the basic fuel injection amount is set for each cylinder as follows.

The fuel injection amount setting means F sets the fuel injection amount for each cylinder by correcting the basic fuel injection amount based on the feedback correction value set for each cylinder, and the drive pulse signal output means G sets the fuel injection amount for each cylinder. A driving pulse signal corresponding to each fuel injection amount is outputted in correspondence to each fuel injection means H provided for each cylinder.

That is, instead of providing the exhaust component detection means B such as an oxygen sensor for each cylinder, the exhaust component detection means B is installed in each exhaust passage collection section that is assembled for each cylinder group consisting of a plurality of cylinders whose exhaust strokes do not overlap. By interposing B and identifying exhaust components detected a predetermined time after the exhaust stroke timing of each cylinder as exhaust components of a predetermined cylinder in a cylinder group, the air-fuel ratio can be detected for each cylinder. , air-fuel ratio feedback control can be performed for each cylinder.

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

In FIG. 2, a four-cylinder internal combustion engine 1 is connected to an air cleaner 2 through an intake duct 3. Air is taken in via the throttle valve 4 and the intake manifold 5.

A branch portion of the intake manifold 5 is provided with a fuel injection valve 6 as a fuel injection means for each cylinder. The fuel injection valve 6 is an electromagnetic fuel injection valve that opens when the solenoid is energized and closes when the energization is stopped. Fuel is injected and supplied under pressure from the pump and adjusted to a predetermined pressure by a pressure regulator.

An ignition plug 7 is provided in the combustion chamber of the engine 1, which ignites a spark to ignite and burn the air-fuel mixture.

From engine 1, exhaust manifold 8° exhaust duct 9. Exhaust gas is discharged via a three-way catalyst 10 and a muffler 11. The three-way catalyst 10 is an exhaust purification device that oxidizes Co and HC in the exhaust components, and also reduces NO8 to convert it into other harmless substances, and when the air-fuel mixture is burned at the stoichiometric air-fuel ratio In this case, the conversion efficiency is the best.

The control unit 12 includes a CPU and a ROM.

It is equipped with a microcomputer including a RAM, an A/D converter, and an input/output interface, and receives input signals from various sensors, performs arithmetic processing as described below, and controls the operation of the fuel injection valve 6. .

As the various sensors described above, a hot wire type or flap type air flow meter 13 is provided in the intake duct 3, and outputs a voltage signal according to the intake air flow ff1Q.

In addition, a crank angle sensor 14 is provided, and in the case of a four-cylinder engine, a reference signal RE for each crank angle 180' is provided.
F (reference signal) and position signal PO3 (unit signal) every 1° or 2° of crank angle are output. Here, by measuring the period of the reference signal REF or the number of occurrences of the position signal PO3 within a predetermined time, it is possible to calculate the engine rotational speed N, and one of the reference signals REF is different from the other. It can be identified by the pulse width and serves as a cylinder discrimination signal for the #l cylinder. Further, a water temperature sensor 15 and the like are provided to detect the cooling water temperature Tw of the water jacket of the engine (2).

Here, the air flow meter 13. The crank angle sensor 14 and the like correspond to engine operating state detection means.

Furthermore, the exhaust manifold 8, as shown in FIG.
Exhaust gas is collected into two groups of cylinders: #1 cylinder and #4 cylinder, and #2 cylinder and #3 cylinder (cylinders whose exhaust strokes are not close to each other are grouped together), and are exhausted via exhaust duct 9. is introduced to the three-way catalyst 10 and the muffler 11, and the two in the exhaust manifold 8
An 02 sensor 16 serving as an exhaust component detection means is provided in each of the exhaust collection parts of the two cylinder groups, and detects the air-fuel ratio of the air-fuel mixture taken into the engine l via the 08 concentration in the exhaust gas. Furthermore, 0! As sensor 16, patent application 1986
More accurate detection is possible by using the No. reduction catalyst layer material proposed by the present applicant in No. 65844.

Here, the CPU of the microcomputer built into the control unit 12 executes the programs (#1 fuel injection amount calculation routine, 0□ sensor output sampling routine, air-fuel ratio feed pack) on the ROM shown as flowcharts in FIGS. The arithmetic processing is performed according to the proportional/integral control routine of the correction coefficient LAMBDA, and fuel injection is controlled.

The basic fuel injection amount setting means, the feedback correction value setting means, the cylinder-specific air-fuel ratio detection means, the fuel injection amount setting means,
The function as a drive pulse signal output means is achieved by the above-mentioned program, and in this embodiment, in order to simplify the explanation, fuel injection control for the #1 cylinder will be explained based on FIGS. 4 to 6. However, for the other cylinders #2 to #4, the same procedure as for cylinder #l is performed.

FIG. 4 is a #1 fuel injection amount calculation routine, that is, a routine for calculating the fuel injection amount to be injected to the #1 cylinder, and is executed at predetermined time intervals.

In step 1 (denoted as Sl in the figure; the same applies hereinafter), the intake air flow rate Q is detected based on the signal from the air flow meter 13, and the engine rotation speed is calculated based on the signal from the crank angle sensor 14. N, water temperature sensor 15
Input the water temperature Tw etc. detected based on the signal from.

In step 2, a basic fuel injection amount Tp=KxQ/N (K is a constant) corresponding to the intake air flow rate per unit rotation is calculated from the intake air flow ff1Q and the engine rotational speed N.

In step 3, ° various correction coefficients C0EF (=1+
KMII+Ktw+ KAs+ Ka+ +...)
is set based on the water temperature Tw, etc.

In the next step 4, a voltage correction numerator s is set based on the battery voltage. This is to correct changes in the injection flow rate of the fuel injection valve 6 due to changes in battery voltage.

In step 5, the actual air-fuel ratio of the #1 cylinder detected in the routine shown in the flowchart in FIG. 5, which will be described later, is compared with the stoichiometric air-fuel ratio, which is the target air-fuel ratio, and set according to the routine shown in the flowchart in FIG. 6. Read the air-fuel ratio feedback correction coefficient LAMBDA□ for the #1 cylinder.

In step 6, fuel injection iTi for the #1 cylinder is calculated according to the following equation.

T i = T p X COE F X LAMBD
Am + + T sIn step 7, the fuel injection amount Ti set in step 6 is set in the output register for the #1 cylinder. As a result, when the predetermined engine rotation synchronization (for example, every rotation) fuel injection timing comes, a drive pulse signal with a pulse width corresponding to the latest set fuel injection amount Ti is applied to the fuel provided in the #1 cylinder. The fuel is applied to the injection valve 6 to perform fuel injection.

In Fig. 5, the oxygen concentration ratio (air-fuel ratio) in the exhaust gas of #1 cylinder is detected. Sensor output voltage V. This is a routine for sampling cylinder #8 at a predetermined timing.
As shown in FIG. 7, the discrimination signal for the first cylinder is output during the intake stroke of the #l cylinder. ) is executed when input.

First, in step 11, it is determined whether the reference signal REF has been input three times since the discrimination signal for the #l cylinder has been input. The time when the reference signal REF is input three times after the discrimination signal for the #1 cylinder is input is when the #1 cylinder is in the exhaust stroke, as shown in FIG. , the Oz sensor output voltage ■ after a predetermined delay time TMDLY after inputting the reference signal REF indicating the exhaust stroke of the #l cylinder. 2 is sampled as indicating the oxygen concentration ratio in the exhaust gas of the #1 cylinder.

Therefore, if the number of inputs of the reference signal REF after the cylinder discrimination signal is not 3 in step 11, the process returns to step 11 and the discrimination is repeated, and when the number of inputs reaches 3 (#l cylinder exhaust When the reference signal REF indicating the stroke is input), the process advances to step 12.

In step 12, a timer is started to measure the time from the reference signal REF indicating the exhaust stroke of the #l cylinder to the sampling timing.

Then, in step 13, the timer T
M and a predetermined delay time TMDLY are compared to determine whether or not the predetermined delay time TMDLY has elapsed.

The predetermined delay time TMDLY is set in consideration of the travel time until the exhaust gas discharged through the exhaust valve reaches the 02 sensor 16 and the response delay time of the 0□ sensor 16. Therefore, this predetermined delay time TMD after the input of the reference signal REF indicating the exhaust stroke of the #l cylinder
When LY has elapsed, it can be determined that the oxygen concentration ratio in the exhaust gas of the #l cylinder has been detected by the 0□ sensor 16 installed at the exhaust gas collecting part of the #1 cylinder and the #4 cylinder, and this In this way, the oxygen concentration ratio of each cylinder can be detected separately in the 0□ sensor 16 exposed to the exhaust gas of the two cylinders.

Note that when the distance from the exhaust valve of each cylinder to the 0□ sensor 16 is different, the time it takes for exhaust gas to reach the 02 sensor 16 from the exhaust valve is different for each cylinder, so the predetermined delay time TMDLY is set for each cylinder. By changing the number of samples, you can perform sampling with high accuracy.

When it is determined that the predetermined delay time TMDLY has elapsed in the read/write mode 13, in the next step 14, the current 0□ sensor 1 is
6 output voltage V. 2 and set this value to #1
Output value corresponding to cylinder exhaust■. Let it be 2□.

As described above, in the case of the present embodiment, one O2 sensor 16 detects the oxygen concentration ratio in the exhaust gas of two cylinders.
By sampling the output voltage VOW of 6, it is determined that exhaust gas from one cylinder is being detected, and the two 02 sensors 16 determine the exhaust oxygen concentration ratio (
There is no need to provide an Ox sensor 16 for each cylinder to detect the air-fuel ratio of each cylinder, resulting in a slight increase in cost compared to conventional systems (02 sensor in a 4-cylinder internal combustion engine). 16) enables air-fuel ratio feedback control for each cylinder.

In a four-cylinder internal combustion engine, the exhaust strokes of the four cylinders do not overlap, but even if the exhaust timing and sampling timing are matched as in this example, the exhaust strokes of each cylinder are continuous, so the exhaust strokes of the four cylinders do not overlap. It is not possible to separate each cylinder. Therefore, in this embodiment, one 02 sensor 1
The exhaust strokes of the cylinders 6 are in charge of are not continuous, so that exhaust gas separation can be performed well.

In addition, since the air-fuel ratio of each cylinder can be detected independently in this way, and the fuel injection MTi can be feedback-controlled for each cylinder, the air-fuel ratio can be controlled to the target air-fuel ratio for each cylinder.
Even if there are various factors that cause variations in the air-fuel ratio between cylinders, fluctuations in the exhaust properties (air-fuel ratio) at the inlet of the three-way catalyst 10 can be sufficiently suppressed, and precious metals such as platinum used in the three-way catalyst lO Even if the exhaust purification ability of the three-way catalyst 10 is lowered by reducing the amount used, sufficiently clean exhaust gas can be obtained.

FIG. 6 shows a proportional/integral control routine, which is executed at predetermined time intervals (for example, Iorms), and is thereby applied to the air-fuel ratio feedback correction coefficient LAMBDA□ for the #1 cylinder (the theory that the air-fuel ratio of the #1 cylinder is the target air-fuel ratio). (feedback correction value) that is set to approximate the air-fuel ratio.

In step 31, it is determined whether air-fuel ratio feedback control conditions are satisfied. Here, the conditions for stopping (clamping) the air-fuel ratio feedback control are, for example, the following cases.

■When starting ■At low water temperature (i) When starting at less than 10'C, until the temperature reaches 75°C (ii) When starting at 10'C or more, until the temperature reaches 30°C ■When operating the engine at high load ■Decelerating operation At the time of idling operation, the OzOx sensor 16 constant air-fuel ratio feedback control condition is satisfied, the 02 sensor 16 which indicates the exhaust oxygen concentration ratio (air-fuel ratio) of the #1 cylinder sampled in the routine shown in FIG. The output voltage V.21 is read, and in the next step 33, the slice level voltage Vrl corresponding to the stoichiometric air-fuel ratio which is the target air-fuel ratio is determined.
By comparing with lf, the air-fuel ratio of #1 cylinder can be determined as rich.
Determine lean.

When the air-fuel ratio is lean (Vozm + < V Air-fuel ratio feedback correction coefficient LAMBDA11 r is set to a predetermined proportional constant 2 with respect to the previous value.
increase by the amount. Otherwise, the process proceeds to step 36, where the air-fuel ratio feedback correction coefficient LAMBDAmt is increased by a predetermined integral constant of 1 minute relative to the previous value, and thus the air-fuel ratio feedback correction coefficient LAMBDA□ is increased at a constant slope. Note that P>>I.

When the air-fuel ratio is rich (■.2111>Lef), the process proceeds from step 33 to step 37, where it is determined whether or not it is the time of reversal from lean to rich (immediately after the reversal), and when the air-fuel ratio is reversed, the process proceeds to step 38. The air-fuel ratio feedback correction coefficient LAMBDA11 r is decreased by a predetermined proportionality constant of 2 minutes from the previous value. If the inversion time is out of bounds, proceed to step 39 and calculate the air-fuel ratio feedback correction coefficient LAMBDAII +
is decreased by a predetermined integral constant of 1 minute from the previous value, and thus the air-fuel ratio feedback correction coefficient LAMBDA*+ is decreased at a constant slope.

In this example, a four-cylinder internal combustion engine was described, but
This is not limited to 4-cylinder internal combustion engines, but if cylinders whose exhaust strokes do not overlap or are not very close to each other are grouped, and a 0□ sensor 16 is provided for each group, each cylinder By dividing the cylinders into groups as described above, the air-fuel ratio can be detected for each cylinder, compared to the case where the 0□ sensor 16 is provided for each cylinder. Even if the number of sensors 16 is reduced, it is possible to detect the air-fuel ratio for each cylinder, thereby suppressing cost increases.

<Effects of the Invention> As explained above, according to the present invention, the air-fuel ratio can be detected for each cylinder without providing exhaust component detection means such as an oxygen sensor for each cylinder, resulting in a significant cost reduction. (In addition to performing air-fuel ratio feedback control for each cylinder, feedback control of the air-fuel ratio for each cylinder eliminates air-fuel ratio variations between cylinders and sufficiently suppresses air-fuel ratio fluctuations. By reducing the amount of precious metal used in the catalyst, the exhaust purification ability can be reduced, which has the effect of reducing the cost of the three-way catalyst.

[Brief explanation of the drawing]

Fig. 1 is a functional block diagram showing the configuration of the present invention, Fig. 2 is a system diagram showing an embodiment of the invention, and Fig. 3 is a plan view for explaining the mounting position of the 02 sensor in Fig. 2. , FIGS. 4 to 6 are flowcharts for explaining fuel injection control in the above embodiment, FIG. 7 is a time chart for explaining the timing of Oz sensor output sampling in the above embodiment, and FIG. 8 is a conventional flowchart. 0□ Sensor mounting is a plan view for explaining the position. 1... Engine 6... Fuel injection valve 8... Exhaust manifold 10... Three-way catalyst 12... Control unit 13... Air flow meter
14...Crank angle sensor 15...Water temperature sensor 16...0□sensor■missing 5 Rihayamoto Seiko Roshiki Kasai! Figure 4 Figure 5

Claims (1)

[Scope of Claims] An engine operating state detection means for detecting an engine operating state including at least a parameter related to the amount of air taken into the engine; an exhaust component detection means for detecting engine exhaust components, which is interposed in each of the exhaust passage collection parts; and an exhaust component detection means for detecting the exhaust stroke timing of each cylinder, and detecting the exhaust stroke timing by the exhaust component detection means after a predetermined time from the exhaust stroke timing. cylinder-by-cylinder air-fuel ratio detection means for specifying an exhaust component as an exhaust component of a predetermined cylinder in the cylinder group and detecting an air-fuel ratio for each cylinder based on the exhaust component; A basic fuel injection amount setting means for setting a basic fuel injection amount based on the engine operating state; and a comparison between the actual air-fuel ratio detected by the cylinder-specific air-fuel ratio detection means and a target air-fuel ratio for each cylinder to determine the actual air-fuel ratio. feedback correction value setting means for setting a feedback correction value for each cylinder to correct the basic fuel injection amount so as to bring the air-fuel ratio closer to the target air-fuel ratio; and feedback correction set for each cylinder by the feedback correction value setting means. a fuel injection amount setting means for setting the fuel injection amount for each cylinder by correcting the basic fuel injection amount based on the value; and a drive pulse corresponding to the fuel injection amount for each cylinder set by the fuel injection amount setting means. An air-fuel ratio feedback control device for an electronically controlled fuel injection type internal combustion engine, comprising: drive pulse signal output means for outputting a signal in correspondence with each of the fuel injection means provided for each cylinder.