JPH0791304A - Fuel supply controller of internal combustion engine - Google Patents

Abstract

PURPOSE:To realize air-fuel ratio learning correction with high accuracy and response without being influenced by ON/OFF of exhaust gas reflux(FGR). CONSTITUTION:Learning of an air-fuel ratio feedback correction coefficient Lalpha is advanced by a means G at the time of theoretical air-fuel ratio control which EGR is realized. On the other hand, a feedback corrective coefficient LLalpha matching the stop condition of the EGR is obtained by making correction by a means (I) based on an EGR rate at the time of learning a learned result during the theoretical air-fuel ratio control, at the time of lean air-fuel ratio control in which the EGR is stopped. A basic fuel pulse width Tp is corrected by a means C by means of the corrective coefficient Lalpha or LLalpha, so as to provide a final fuel injection pulse width Ti by a means K.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel supply control device for an internal combustion engine, and more particularly to a technique for learning and correcting a fuel supply amount.

[0002]

2. Description of the Related Art Conventionally, an exhaust gas recirculation (hereinafter abbreviated as "EGR") device has been known in which a combustion temperature is lowered by recirculating a part of engine exhaust gas to an intake system, thereby reducing NOx emission amount. ing. On the other hand, by detecting the air-fuel ratio of the engine intake air-fuel mixture via the oxygen concentration in the exhaust gas, the air-fuel ratio that learns the correction value of the fuel injection amount required to obtain the target air-fuel ratio for each engine operating state Learning control is known (JP-A-4-
1439 gazette etc.).

Further, by setting the target air-fuel ratio to an air-fuel ratio (for example, 22 to 25) that is significantly leaner than the stoichiometric air-fuel ratio,
An engine aimed at improving fuel efficiency has also been proposed (see Japanese Patent Laid-Open No. 2-153243, etc.). Here, when EGR is executed when combustion is performed at the lean air-fuel ratio, E
Since GR may become a disturbance factor and greatly deteriorate combustion stability, EGR is executed only when the target air-fuel ratio is near the stoichiometric air-fuel ratio, and EGR is executed during lean air-fuel ratio combustion.
It is desired to stop.

[0004]

As described above, when the EGR is selectively executed in response to the switching of the target air-fuel ratio, unburned gas and oxygen are recirculated along with the EGR. As a result, the required level of the correction value required to obtain the target air-fuel ratio changes depending on the presence or absence of EGR. Therefore, for example, if the target air-fuel ratio near the stoichiometric air-fuel ratio is used and the result learned during EGR is applied as it is during lean combustion control in which EGR is stopped, an error will occur in air-fuel ratio correction control. I will end up.

Therefore, as described above, the theoretical air-fuel ratio (EG
When the lean air-fuel ratio control (E
When the configuration is used as it is for the GR stop state),
Even if an error of the air-fuel ratio control occurs, it is necessary to set the target of the lean air-fuel ratio to the rich side than it should be, so that the combustion stability is not greatly impaired, and the rich side limit of lean combustion is There is a problem that the control range of the lean air-fuel ratio control is narrowed because it is determined from the request for the NOx emission amount.

Here, if the learning result at the time of EGR execution is not applied as it is when EGR is stopped, but is made to be learned in each state (see Japanese Patent Laid-Open No. 4-1439), it is possible that the learning progresses. Optimal learning correction can be performed regardless of whether EGR is executed or stopped. With such a configuration, learning is performed individually according to execution or stop of EGR even under the same engine load and engine speed conditions. Therefore, when the target air-fuel ratio is frequently switched, the learning effect is difficult to obtain in each air-fuel ratio control state.

The present invention has been made in view of the above problems, and it is possible to implement the learning correction control of the fuel supply amount that can respond to the difference in the correction request level depending on the presence or absence of EGR, and can obtain the effect of the learning control with good response. Aim to achieve.

[0008]

Therefore, a fuel supply control system for an internal combustion engine according to the present invention is constructed as shown in FIG. In FIG. 1, the exhaust gas recirculation unit recirculates a part of the engine exhaust gas to the engine intake system at a recirculation rate according to the engine operating state. Further, the exhaust gas recirculation execution control means switches execution / stop of exhaust gas recirculation by the exhaust gas recirculation means in accordance with engine operating conditions.

On the other hand, the correction value learning means corrects the fuel supply amount to the engine based on the combustion state of the engine detected by the combustion state detection means when the exhaust gas recirculation execution control means is executing the exhaust gas recirculation. The feedback correction value for learning is learned. Then, the correction value storage means stores the feedback correction value learned by the correction value learning means for each engine operating state.

Further, the stop-time correction value setting means, when the exhaust gas recirculation is stopped by the exhaust gas recirculation execution control means, the exhaust gas recirculation rate at the time of learning the feedback correction value stored in the correction value storage means. And a feedback correction value corresponding to the exhaust gas recirculation stop state is set. Then, the fuel supply correction means corrects and controls the fuel supply amount to the engine based on the feedback correction value.

[0011]

According to this structure, the feedback correction value is learned while the exhaust gas recirculation is being performed, and the fuel supply amount is corrected using the learning result. On the other hand, when the exhaust gas recirculation is stopped, the stored value of the learning result at the time of executing the exhaust gas recirculation is corrected by the exhaust gas recirculation rate at the time of learning,
A feedback correction value corresponding to when the exhaust gas recirculation is stopped is set.

That is, the correction level required when the exhaust gas recirculation is stopped is estimated based on the learning result when the exhaust gas recirculation is performed and the exhaust gas recirculation rate when the learning is performed,
The estimated result is used to correct the fuel supply amount when the exhaust gas recirculation is stopped.

[0013]

EXAMPLES Examples of the present invention will be described below. FIG. 2 is a diagram showing the system configuration of the embodiment. In FIG. 2, fuel injection valves 3a to 3d are provided for each cylinder in a branch portion of an intake manifold 2 of the engine 1, and intake air adjusted by a throttle valve 4 and the fuel injection valve 3a are provided.
A mixture is formed by the fuel injected and supplied from ~ 3d and sucked into the cylinder.

The opening operation of each of the fuel injection valves 3a to 3d is controlled by a control unit 5 containing a microcomputer. The microcomputer incorporated in the control unit 5 includes a CPU 5a that performs various kinds of arithmetic processing, and a ROM 5b that stores various data necessary for the arithmetic processing. Signals from various sensors are input to the control unit 5 for the fuel injection control.

As the various sensors, a crank angle sensor 6 is provided in the distributor,
The crank angle sensor 6 outputs a signal for each unit angle and a signal for each reference piston position. Here, the engine speed Ne is calculated based on the detection signal from the crank angle sensor 6. An air flow meter 7 for detecting the engine intake air amount Qa is provided upstream of the throttle valve 4, and a water temperature sensor 8 for detecting the cooling water temperature Tw in the cooling jacket is provided. Is provided with a potentiometer type throttle sensor 9 for detecting the opening TVO.

Further, at the collecting portion of the exhaust manifold 10 of the engine 1, there is a sensor whose output changes in response to the oxygen concentration in the exhaust gas which correlates with the air-fuel ratio of the engine intake air-fuel mixture. Well-known wide-range air-fuel ratio sensor 11 (Sankaido Co., Ltd.) that can linearly detect the rich to lean region
“Internal combustion engine” issued on May 1, 1992) is provided as a combustion state detecting means.

A vehicle speed sensor 12 for extracting a rotation signal from an output shaft of a transmission (not shown) combined with the engine 1 is also provided. On the other hand, the engine 1 of this embodiment is provided with an exhaust gas recirculation device (EGR device) 13 as exhaust gas recirculation means. The EGR device 13 includes an EGR passage 14 for communicating an exhaust system downstream of the wide range air-fuel ratio sensor 10 and an intake system downstream of the throttle valve 4, and an EGR control valve interposed in the EGR passage 14. It consists of fifteen. The EGR control valve 15 is controlled by the control unit 5, and the control unit 5 adjusts the opening degree of the EGR control valve 15 based on the EGR rate data set in advance for each engine operating state. Variable control.

Further, the control unit 5 sets the target air-fuel ratio of the engine intake air-fuel mixture to an air-fuel ratio near the theoretical air-fuel ratio and an air-fuel ratio significantly leaner than the theoretical air-fuel ratio (hereinafter, simply Lean air-fuel ratio). Then, in order to form the air-fuel mixture having the set target air-fuel ratio, a final fuel injection pulse width Ti is calculated, and an injection pulse signal having the pulse width Ti is given at a predetermined timing in synchronization with engine rotation. 3a-3d
Output to.

The control unit 5 uses the exhaust gas recirculation rate set in advance for each engine operating state to set the EG
Although the opening degree of the R control valve 15 is controlled, when the lean air-fuel ratio is set as the target air-fuel ratio, the EGR becomes a disturbance factor and impairs combustion stability. The EGR is executed only when the engine is stopped and the target air-fuel ratio is set near the stoichiometric air-fuel ratio. The EGR execution / stop switching control function according to the target air-fuel ratio of the control unit 5 corresponds to the exhaust gas recirculation execution control means in the present embodiment.

FIG. 3 is a block diagram showing the fuel control function of the control unit 5 in this embodiment. In FIG. 3, the intake air amount Qa detected by the intake air amount detecting means A corresponding to the air flow meter 7.
And the engine speed Ne detected by the engine speed detection means B corresponding to the crank angle sensor 6, the basic fuel pulse width calculation means C calculates the basic fuel pulse width Tp.

On the other hand, on the basis of the detection result of the vehicle operating state detecting means D such as the water temperature sensor 8 and the throttle sensor 9, the operating state correction coefficient calculating means E operates the operating state for correcting the basic fuel pulse width Tp. The correction coefficient Coef is calculated. Further, based on the detection result of the combustion state detecting means F corresponding to the wide range air-fuel ratio sensor 10, a feedback correction coefficient L for making the actual air-fuel ratio close to the target air-fuel ratio.
alpha (feedback correction value) is the correction coefficient Lalpha stored at the corresponding grid point in the correction coefficient storage map H described later.
Is calculated as a reference value by the feedback correction coefficient calculation means G, and the calculated feedback correction coefficient Lalpha is updated and stored in the feedback correction coefficient storage map H (see FIG. 5) so that the correction request level is changed for each operating state. Learned. The function of storing the calculation result of the feedback correction coefficient calculation means G in the map H corresponds to the correction value learning means in this embodiment.

Here, the feedback correction coefficient Lal
pha is learned and stored in the map H only when EGR is performed by the EGR device 13 under the condition that an air-fuel ratio near the stoichiometric air-fuel ratio is set as the target air-fuel ratio. Then, when the lean air-fuel ratio is set as the target air-fuel ratio (condition where EGR is stopped), EGR
EGR correction factor REGR stored in the correction factor storage means I
Based on (see FIG. 6), the map data learned at the time of executing the EGR is corrected and calculated by the lean operation correction coefficient calculating means J (stop-time correction value setting means), and the correction result is fed back to the lean air-fuel ratio. It is set as the correction coefficient LLalpha.

Then, in the fuel injection pulse width calculation means K (fuel supply correction means), the basic fuel pulse width Tp, the operation state correction coefficient Coef, and the feedback correction coefficient Lalph.
The final fuel injection pulse width Ti is calculated based on a (or LLalpha). Next, according to the flow chart of FIG. 4, the state of the arithmetic processing performed according to the control block diagram shown in FIG. 3 will be described in detail.

The routine shown in the flow chart of FIG. 4 is executed at regular intervals (for example, 4 msec). Further, as shown in the flow chart of FIG. 4, in the present embodiment, the control unit 5 is provided with software as the correction value learning means, the stop time correction value setting means, and the fuel supply correction means. The correction value storage means corresponds to a memory built in the control unit 5.

In the flowchart of FIG. 4, first, P
At 1, the engine speed Ne calculated based on the detection signal of the crank angle sensor 6 is read. Next, at P2, the intake air amount Qa detected by the air flow meter 7 is read. Then, at P3, the basic fuel pulse width Tp is calculated based on the engine speed Ne and the intake air amount Qa read at P1 and P2 respectively.

At P4, parameters indicating the engine operating state such as the cooling water temperature Tw detected by the water temperature sensor 8 are read. Then, at P5, the operating condition correction coefficient Coef is calculated based on the information such as the cooling water temperature Tw read at P4.
To calculate. At P6, the output value of the wide range air-fuel ratio sensor 10 is read, and at next P7, the feedback correction coefficient Lalpha for correcting the basic fuel pulse width Tp is calculated based on the read output value of the wide range air-fuel ratio sensor 10. The calculation is performed so that the detected actual air-fuel ratio approaches the target air-fuel ratio.

At P8, the feedback correction coefficient L
It is determined whether or not the driving condition allows learning of alpha. The learning condition that can be learned is that at least the stoichiometric air-fuel ratio is being feedback-controlled (EGR is being executed),
And, for example, it is assumed that the engine is in a steady state. When it is determined in P8 that the learning condition is satisfied, the process proceeds to P9, in which the calculated feedback correction coefficient Lalpha is used as correction request data corresponding to the current operating state (engine load, rotation speed), engine load (basic fuel). Table in which grid points are determined using the pulse width Tp) and the rotation speed Ne as parameters (feedback correction coefficient storage map H: see FIG. 5).
It is updated and memorized in and learned.

The learning result is referred to for each operating state, and the feedback correction coefficient Lalpha is calculated with the reference value as a reference. At P10, it is determined whether the lean air-fuel ratio is in the operating region where the target air-fuel ratio should be set. In particular,
As shown in FIG. 7, the engine load (basic fuel pulse width T
p) and the engine speed Ne, which correspond to the lean air-fuel ratio control region set as parameters, and the cooling water temperature Tw.
Is equal to or higher than a predetermined temperature and is still in steady operation (the change rate of the throttle valve opening TVO is small) as a condition for lean air-fuel ratio control.

When it is determined at P10 that the lean air-fuel ratio control condition is not satisfied, that is, when the operating condition is to be controlled to the target air-fuel ratio near the stoichiometric air-fuel ratio, P
Proceeding to step 15, the basic fuel pulse width Tp is corrected by the feedback correction coefficient Lalpha and the operating state correction coefficient Coef calculated as described above, and the correction result is determined as the final fuel injection pulse width Ti (= Tp × Coef × Lalpha)
Set to.

On the other hand, when it is determined at P10 that the lean air-fuel ratio control condition is satisfied, the injection is controlled with the lean air-fuel ratio as the target, and the EGR is also stopped. As a result, the learning correction storage of the feedback correction coefficient Lalpha in P9 is not performed. Here, the feedback correction coefficient Lalpha learned and stored in P9 is a value learned when the EGR is executed with the target air-fuel ratio being close to the stoichiometric air-fuel ratio. Therefore, when the EGR is stopped, , Due to the influence of the recirculation of unburned gas and oxygen due to EGR, the correction coefficient does not correspond to the required level even if the engine load and the engine speed are the same, and if the learning result is used as it is, the control error (target lean air-fuel ratio Is controlled to leaner side).

However, since the difference between the correction request levels is due to the presence or absence of EGR, the EGR is determined from the learning result during execution of EGR and the EGR rate data during the learning.
The required correction level when stopping the can be estimated. Therefore, if it is determined at P10 that the lean air-fuel ratio control condition is satisfied, the routine proceeds to P11, where the current operating condition is based on the EGR rate map (see FIG. 8) referred to by the control of the EGR control valve 15. The EGR rate when the feedback correction coefficient Lalpha corresponding to is learned.

At the next P12, the correction rate REGR for correcting the feedback correction coefficient Lalpha learned at the time of executing EGR to a value corresponding to the EGR stop state is set based on the EGR rate obtained at P11. Yes (Fig. 6
reference). At P13, the correction factor REGR set at P12 is
By multiplying the feedback correction coefficient Lalpha stored corresponding to the corresponding driving condition on the learning map, the feedback correction coefficient Lalpha learned and adapted to the execution state of EGR is corrected to the EGR stopped state. Convert to coefficient LLalpha.

At P14, the basic fuel pulse width Tp is corrected using the feedback correction coefficient LLalpha and the operating state correction coefficient Coef corresponding to the EGR stop state obtained at P13, and the final lean air-fuel ratio control time is corrected. The fuel injection pulse width Ti (= Tp * Ceof * LLalpha) is obtained. With this configuration, the feedback correction coefficient Lalpha is learned only when the target air-fuel ratio is set near the stoichiometric air-fuel ratio and the EGR is executed. However, the learning result is the EGR rate when the learning is performed. By correcting the lean air-fuel ratio based on the above, the value is corrected to a value corresponding to the lean air-fuel ratio control in which the EGR is stopped, in other words, a value corresponding to the difference in the correction request level due to the presence or absence of EGR, and is used during the lean air-fuel ratio control.

Therefore, by using the learning result at the time of executing EGR, appropriate learning correction can be performed not only when the EGR is executed but also when the EGR is stopped, and immediately after the EGR is stopped (to the lean air-fuel ratio control). Immediately after the transition), appropriate learning correction can be expected. Therefore, it is not necessary to preliminarily rich-shift the target lean air-fuel ratio in consideration of the deviation of the learning correction control, and it becomes possible to improve the fuel efficiency by promoting leaning of the target air-fuel ratio.

In the above embodiment, the engine load (basic fuel pulse width Tp) and the engine speed N in the EGR rate table to be referred when obtaining the EGR rate and the learning table for learning and storing the feedback correction coefficient Lalpha.
If the grid points determined by e and e are made common, the interpolation calculation for comparing and referencing as data corresponding to the same engine load and engine speed is not required, and it is expected that the calculation speed is increased and the control accuracy is improved.

In the above embodiment, the wide range air-fuel ratio sensor 10 is used as the combustion state detecting means, and the air-fuel ratio feedback learning control for obtaining the target air-fuel ratio is described.
For example, an in-cylinder pressure sensor that detects the pressure in the cylinder may be provided as the combustion state detecting means, and the combustion pressure may be feedback-controlled. Next, a second embodiment will be described.

FIG. 9 is a control function block diagram in the second embodiment. A lean combustion feedback correction coefficient storage map L is added to the control block diagram of the first embodiment shown in FIG. The only difference is that The lean combustion feedback correction coefficient storage map L (stop time correction value storage means) is based on the learning result at the time of performing EGR in the lean operation correction coefficient calculation means J based on the EGR rate when the learning is performed. The correction coefficient LLalph that has been corrected and converted to the one for EGR stop (for lean combustion)
It is a map in which a is stored as a lean combustion learning value LMLalpha for each operating state.

That is, in the second embodiment, the learning result at the time of executing the EGR is corrected to a value suitable for the EGR stop based on the EGR rate, and the corrected value is stored as the learning value for the EGR stop. By doing so, learning for EGR stop (during lean combustion) can be performed based on the learning result during EGR execution. Therefore, relatively accurate learning correction is applied from the beginning of lean combustion, and
By advancing the learning based on the learning correction level (correction coefficient obtained from the learning result at the time of executing the EGR), it becomes possible to perform the learning capable of accurately responding to the correction request for each operating state during lean combustion. ing.

Here, according to the flowchart of FIG.
The state of learning control in the second embodiment will be described in detail.
In the flowchart of FIG. 10, P21 to P26 perform exactly the same processing as P1 to P6 in the flowchart of FIG. 4, so the description of each step of P21 to P26 will be omitted, and the processing content will be described from P27.

At P27, it is judged if the lean air-fuel ratio is in the operating region where the target air-fuel ratio should be set. Specifically, as shown in FIG. 7, it corresponds to the lean air-fuel ratio control region in which the engine load (basic fuel pulse width Tp) and the engine speed Ne are set as parameters in advance, and the cooling water temperature T
If w is above a predetermined temperature and still in steady operation,
This is the condition for lean air-fuel ratio control.

When it is judged at P27 that the lean air-fuel ratio control condition is not satisfied and the target air-fuel ratio is set to an air-fuel ratio near the stoichiometric air-fuel ratio, the routine proceeds to P28. At P28, the feedback correction coefficient Lalpha for correcting the basic fuel pulse width Tp is based on the learning value stored in the map, and the actual air-fuel ratio detected based on the output value of the wide-range air-fuel ratio sensor 10 is set. The calculation is performed so as to approach the target air-fuel ratio.

At P29, the feedback correction coefficient L
It is determined whether or not the driving condition allows learning of alpha. When it is determined in P29 that the learning condition is satisfied, P30
And the calculated feedback correction coefficient Lalph
Let a be the correction request data corresponding to the current operating state (engine load, rotation speed), and set the engine load (basic fuel pulse width T
p) and the number of revolutions Ne as parameters to determine the grid points (feedback correction coefficient storage map H)
It is updated and memorized in and learned.

Then, at P31, the feedback correction coefficient Lalpha and the operating state correction coefficient Coef calculated above are calculated.
The basic fuel pulse width Tp is corrected in accordance with to set the final fuel injection pulse width Ti corresponding to the normal air-fuel ratio control state. On the other hand, when it is determined at P27 that the lean control condition is satisfied, the program proceeds to P32, at which it is determined whether or not the target lean air-fuel ratio and the actual air-fuel ratio detected by the wide-range air-fuel ratio sensor 10 substantially match. .

When it is determined at P32 that there is a deviation between the target lean air-fuel ratio and the actual air-fuel ratio, the routine proceeds to P33, where the EGR rate applied when EGR is executed under the current operating conditions is mapped. (See FIG. 8), and then at P34, the EGR correction rate REGR is calculated from the EGR rate (see FIG. 6). Then, at P35, the feedback correction coefficient Lalpha learned and stored during EGR execution (normal air-fuel ratio control) is multiplied by the EGR correction rate REGR to obtain the correction coefficient LLalph corresponding to the EGR stop state.
Convert to a.

Subsequently, at P36, the feedback correction coefficient LLalpha calculated at P35 is used as a learning value LMLalpha for lean combustion, and a map for lean combustion (FIG. 11).
When the process proceeds from P36 to P38, the final fuel injection pulse width Ti for lean air-fuel ratio control is based on the feedback correction coefficient LLalpha obtained by the correction by the EGR correction rate REGR. Is calculated.

On the other hand, when it is determined at P32 that the target lean air-fuel ratio and the actual air-fuel ratio are substantially the same, the feedback correction coefficient LMLalpha for the corresponding operating state is referred to with reference to the lean combustion map (see FIG. 11). Find, then P38
By proceeding to, the final fuel injection pulse width Ti is calculated based on the map reference value. As described above, in the second embodiment, the map for learning and storing the feedback correction coefficient Lalpha is used as the map for stoichiometric air-fuel ratio control (when executing EGR).
Map and for lean air-fuel ratio control (when EGR is stopped)
The map for the stoichiometric air-fuel ratio control is normally learned, while the map for the lean air-fuel ratio control has an air-fuel ratio deviation by the learning correction using the map data. In this case, the result learned at the time of executing EGR is rewritten to a value obtained by correcting it based on the EGR rate at that time, and when the lean air-fuel ratio can be controlled by the learning correction using the map data, The map data is used as it is for correction.

According to this structure, when the learning in the lean air-fuel ratio control state is not progressing and the air-fuel ratio close to the target lean air-fuel ratio cannot be controlled by the correction using the learned value,
Since the learning value obtained by correcting the result learned in the EGR execution state based on the EGR rate is applied, the learning correction close to the required level can be performed from an early stage, and in this manner, the learning correction close to the required level can be performed. By further advancing the learning for each operating state from the state, it becomes possible to perform the correction control in a lean air-fuel ratio control state at an early stage with high accuracy corresponding to the difference in the correction request for each operating state.

[0048]

As described above, according to the present invention, E
Since the result learned in the GR execution state is corrected based on the EGR rate when the learning is performed, the correction value corresponding to the EGR stop state is used for correction.
There is an effect that the learning control effect can be obtained with good response while responding to the difference in correction request depending on the presence or absence of GR.

[Brief description of drawings]

FIG. 1 is a block diagram showing the basic configuration of the present invention.

FIG. 2 is a system schematic diagram showing an embodiment of the present invention.

FIG. 3 is a block diagram showing a control function of the first embodiment.

FIG. 4 is a flowchart showing the control contents in the first embodiment.

FIG. 5 is a diagram showing a learning map of a feedback correction coefficient.

FIG. 6 is a diagram showing a correction rate REGR according to an EGR rate.

FIG. 7 is a diagram showing a lean combustion region.

FIG. 8 is a diagram showing a map of an EGR rate.

FIG. 9 is a block diagram showing the control function of the second embodiment.

FIG. 10 is a flowchart showing the control contents of the second embodiment.

FIG. 11 is a diagram showing a learning map for lean combustion.

[Explanation of symbols]

 1 Internal Combustion Engine 2 Intake Manifold 3a-3d Fuel Injection Valve 4 Throttle Valve 5 Control Unit 6 Crank Angle Sensor 7 Air Flow Meter 8 Water Temperature Sensor 9 Throttle Sensor 10 Exhaust Manifold 11 Wide Range Air-Fuel Ratio Sensor 12 Vehicle Speed Sensor 13 EGR Device 14 EGR Passage 15 EGR Control valve

Claims (1)

[Claims] 1. A combustion state detecting means for detecting a combustion state of an engine, an exhaust gas recirculation means for recirculating a part of engine exhaust gas to an engine intake system at a recirculation rate according to an engine operating state, and an exhaust gas by the exhaust gas recirculation means. Exhaust gas recirculation execution control means for performing switching control of execution / stop of recirculation according to engine operating conditions, and of the engine detected by the combustion state detection means when exhaust gas recirculation is executed by the exhaust gas recirculation execution control means. A correction value learning means for learning a feedback correction value for correcting the fuel supply amount to the engine based on the combustion state, and a correction value for storing the feedback correction value learned by the correction value learning means for each engine operating state. When the exhaust gas recirculation is stopped by the storage unit and the exhaust gas recirculation execution control unit, the feedback correction value stored in the correction value storage unit is learned. A correction value setting means for stop time which corrects based on the air recirculation rate and sets a feedback correction value corresponding to the exhaust gas recirculation stop state, and a fuel which corrects and controls the fuel supply amount to the engine based on the feedback correction value. A fuel supply control device for an internal combustion engine, comprising: a supply correction means.