JPH07293347A - Exhaust reflux control device for internal combustion engine - Google Patents

Abstract

PURPOSE:To keep a specified exhaust reflux ratio by correcting a control rate correspondingly to variation of the exhaust reflux ratio caused by pollution of a valve or the like. CONSTITUTION:An air amount as a mass flow rate detected by a hot-wire flow meter when exhaust reflux is not conducted is stored in very operation area which is prepared based on a throttle valve opening TVO and an engine speed Ne (S2, S3). When exhaust reflux is conducted, an actual exhaust reflux rate is calculated based on the detected air amount and the stored intake amount (S2, S4, S5, S6, S7). Based on the calculated actual exhaust circulation ratio, an actually obtained exhaust reflux ratio is learned (S9) in respect to a required exhaust reflux ratio (S8).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas recirculation control device for an internal combustion engine, which recirculates part of engine exhaust gas to an intake system.

[0002]

2. Description of the Related Art Conventionally, in an internal combustion engine for automobiles,
As a device for reducing NOx in the engine exhaust, a part of the engine exhaust is returned to the intake manifold (EGR: E
There is known an exhaust gas recirculation device that lowers the maximum combustion temperature to reduce the production of NOx by xhaust gas recirculation (see JP-A-4-81557).

In some of the exhaust gas recirculation devices, the opening degree of a valve provided in the exhaust gas recirculation passage is adjusted by, for example, a step motor in order to appropriately control the exhaust gas recirculation rate according to operating conditions.

[0004]

However, if the particulates contained in the exhaust adhere to the valve provided in the exhaust gas recirculation passage or if the valve is arranged on the intake side, blow-by gas is used. There is a case where dirt adheres due to the influence of the above, and the actual opening area with respect to the valve opening control amount changes due to the adhesion of the dirt and the like, and thus the exhaust gas recirculation amount (exhaust gas recirculation rate) changes (see FIG. 8). ) Was a problem.

The present invention has been made in view of the above problems, and provides an exhaust gas recirculation control device capable of maintaining a desired exhaust gas recirculation rate even if the opening area changes with respect to the control amount due to the dirt or the like. With the goal.

[0006]

Therefore, an exhaust gas recirculation control device for an internal combustion engine according to the invention of claim 1 is constructed as shown in FIG. In FIG. 1, the exhaust gas recirculation control means is
It is a means for controlling an exhaust gas recirculation amount for recirculating a part of the engine exhaust gas to the engine intake system.

Further, the intake air amount detecting means directly detects the intake air amount of the engine as a mass flow rate, and the intake air amount storing means is operated in the state where the exhaust gas recirculation is cut off by the exhaust gas recirculation control means. The intake air amount detected by the intake air amount detecting means is updated and stored for each of the plurality of operating regions. Then, the control amount correction means is an intake air amount detected by the intake air amount detection means while the exhaust gas recirculation control means is performing exhaust gas recirculation, and the intake air amount stored in the intake air amount storage means. The control amount of the exhaust gas recirculation by the exhaust gas recirculation control means is corrected based on the air amount.

In the exhaust gas recirculation control device for an internal combustion engine according to a second aspect of the present invention, the intake air amount storage means stores the intake air amount for each operating region divided into a plurality of engine speeds and throttle valve openings. It is configured to remember. Claim 3
In the exhaust gas recirculation control device for an internal combustion engine according to the invention described above, the intake air amount storage means stores the intake air amount for each of the operating regions divided into a plurality of engine rotation speeds and suction negative pressures.

In the exhaust gas recirculation control device for an internal combustion engine according to a fourth aspect of the present invention, the control amount correction means is detected by the intake air amount detection means while the exhaust gas recirculation control means is performing the exhaust gas recirculation. An exhaust gas recirculation ratio calculating unit for calculating an exhaust gas recirculation ratio based on the intake air amount and the intake air amount stored in the intake air amount storage unit;
A control characteristic for correcting the correlation between the required exhaust gas recirculation rate and the control amount based on the difference between the exhaust gas recirculation rate calculated by the exhaust gas recirculation rate calculation means and the required exhaust gas recirculation rate preset based on the engine operating state. And a correcting means.

In the exhaust gas recirculation control device for an internal combustion engine according to a fifth aspect of the present invention, the control amount correction means is on an operation area divided into a plurality of areas in the intake air amount storage means, and the corresponding operation area and intake air at that time. The control amount is corrected by using the intake air amount stored in any one of the preset operating regions as the operating regions in which the air amounts are substantially the same.

[0011]

In the exhaust gas recirculation control device for the internal combustion engine according to the first aspect of the invention, when the exhaust gas recirculation is cut off,
The intake air amount of the engine detected as the mass flow rate is updated and stored for each operating region. When exhaust gas recirculation is being performed, the intake air amount stored at the time of shutting off the exhaust gas recirculation is compared with the detected value of the intake air amount at that time to obtain the actual exhaust gas return at that time. Knowing the flow rate (exhaust gas recirculation ratio), the control amount is corrected to obtain the desired exhaust gas recirculation amount (recirculation ratio).

That is, when the exhaust gas recirculation is performed, the fresh air inflow air amount detected by the intake air amount detecting means is reduced by the exhaust gas recirculation amount, so that when the exhaust gas recirculation is cut off in advance. If the intake air amount is stored, the exhaust gas recirculation amount (recirculation rate) can be detected as a reduction amount with respect to the air amount. Then, if the control amount is corrected in such a direction that the detected exhaust gas recirculation amount (recirculation ratio) approaches the desired value, even if the correlation between the control amount and the actual exhaust gas recirculation amount (recirculation ratio) changes, It becomes possible to perform exhaust gas recirculation control for a predetermined period.

In the exhaust gas recirculation control device for an internal combustion engine according to the second aspect of the present invention, the engine recirculation speed and the throttle valve opening, which are parameters for determining the volume flow rate of the engine intake air, are divided into a plurality of operating regions. The intake air amount detected as the mass flow rate is updated and stored so that the change in the air amount as the mass flow rate can be detected for each operating region determined by the engine speed and the throttle valve opening.

Further, in the exhaust gas recirculation control device for an internal combustion engine according to the third aspect of the present invention, each operating region is divided into a plurality of regions by the engine rotation speed and the suction negative pressure, which are parameters for determining the volume flow rate of the engine intake air. In addition, the intake air amount detected as the mass flow rate is updated and stored so that a change in the air amount as the mass flow rate can be detected for each operating region determined by the engine speed and the suction negative pressure.

In the exhaust gas recirculation control device for an internal combustion engine according to the fourth aspect of the present invention, the exhaust gas recirculation rate is calculated based on the air amount stored at the time of shutting off the exhaust gas recirculation and the air amount detected at the time of exhaust gas recirculation. Based on the difference between the calculated exhaust gas recirculation rate and the required exhaust gas recirculation rate at that time, the correlation between the required exhaust gas recirculation rate and the control amount is corrected, and the control amount that actually obtains the required exhaust gas recirculation rate becomes the required exhaust gas recirculation rate. It can be set based on.

In the exhaust gas recirculation control device for an internal combustion engine according to the fifth aspect of the present invention, when comparing the intake air amount stored in the storage means with the intake air amount detected in the state of performing exhaust gas recirculation. Even if the intake air amount is not stored in the operating region corresponding to the operating condition at that time, the intake air amount is stored in either of the operating regions where the intake air amount is approximately the same as the corresponding operating region. If the intake air amount is set as a comparison target, the control amount can be corrected even when the intake air amount is not stored in the entire operating region.

[0017]

EXAMPLES Examples of the present invention will be described below. In FIG. 2 showing the system configuration of one embodiment, the internal combustion engine 1 is
Air is taken in through the air cleaner 2, the intake duct 3, and the intake manifold 4. The intake duct 3 is provided with a butterfly-type throttle valve 5 interlocked with an accelerator pedal (not shown), and the throttle valve 5 adjusts the intake air amount of the engine.

An electromagnetic fuel injection valve 6 is provided for each cylinder in each branch portion of the intake manifold 4, and a predetermined space is provided by electronically controlling the amount of fuel injected and supplied from the fuel injection valve 6. A fuel-air mixture is formed. The air-fuel mixture sucked into the cylinder through the intake valve 7 is ignited and burned by spark ignition by the spark plug 8, and the combustion exhaust gas is discharged through the exhaust valve 9 and guided to a catalyst (not shown) and a muffler by the exhaust manifold 10. Get burned.

The exhaust manifold 10 (exhaust system)
An exhaust gas recirculation passage 11 is provided for communicating between the exhaust gas recirculation passage 11 and the intake manifold 4 (intake system), and an EGR control valve 12 is provided in the exhaust gas recirculation passage 11. When the EGR control valve 12 is opened, part of the exhaust gas is recirculated to the engine intake system due to the pressure difference between the exhaust system and the intake system, and the exhaust gas recirculation lowers the combustion temperature, thereby reducing the NOx emission amount. Is planned. The EGR control valve 12 of the present embodiment is configured to open the valve body by a step motor.

The control unit 13 for controlling the fuel injection valve 6 and the EGR control valve 12 is constituted by including a microcomputer, and the intake air amount signal Q from the hot wire type air flow meter 14 and the throttle valve opening from the throttle sensor 15 are opened. The degree signal TVO and the crank angle signal (engine rotation signal) from the crank angle sensor 16 are input. The hot wire air flow meter 14 directly detects the intake air amount of the engine 1 as a mass flow rate based on the resistance change of the temperature-sensitive resistance due to the intake air amount. Equivalent to.

The throttle sensor 15 detects the opening TVO of the throttle valve 5 with a potentiometer. The crank angle sensor 16 includes, for example, an electromagnetic pickup that detects a ring gear of a flywheel, and outputs a detection pulse for each unit angle. here,
The engine rotation speed Ne can be calculated based on the detection signal from the crank angle sensor 16.

The control unit 13 determines the required exhaust gas recirculation rate based on the engine operating conditions, and determines the control pulse (control amount) to be output to the step motor of the EGR control valve 12 based on the required exhaust gas recirculation rate. At the same time, the fuel injection amount of the fuel injection valve 6 is controlled. The control of the injection amount of the fuel injection valve 6 is performed as follows.

That is, based on the intake air amount Q detected by the hot wire air flow meter 14 and the engine rotation speed Ne calculated from the detection signal from the crank angle sensor 16, the basic fuel injection amount Tp (= K × Q). / Ne: K is a constant), and the final fuel injection amount Ti is obtained by correcting the basic fuel injection amount Tp according to the operating conditions such as the cooling water temperature. Then, a drive pulse signal having a pulse width corresponding to the fuel injection amount Ti is output to the fuel injection valve 6 at a predetermined timing. The fuel, which is adjusted to a predetermined pressure by a pressure regulator (not shown), is supplied to the fuel injection valve 6, and the fuel is injected and supplied in an amount proportional to the pulse width of the drive pulse signal.

On the other hand, the control of the EGR control valve 12 (exhaust gas recirculation control) by the control unit 13 as the exhaust gas recirculation control means basically determines the required exhaust gas recirculation ratio according to the engine load and the engine speed Ne. The required exhaust gas recirculation rate is converted into a control pulse (control amount) for the step motor. Next, the state of exhaust gas recirculation control by the control unit 13 will be described in detail with reference to the flowcharts of FIGS.

In the present embodiment, the functions of the exhaust gas recirculation control means, the intake air amount storage means, the control amount correction means, the exhaust gas recirculation rate calculation means, and the control characteristic correction means are the same as those shown in FIG.
And the control unit 13 is provided as shown in the flowchart of FIG. In the flowchart of FIG. 3, step 1 (denoted as S1 in the figure. The same applies hereinafter).
Then, the intake air amount Q (mass flow rate per unit time) detected by the hot wire air flow meter 14 is read.

In step 2, the EGR control valve 12 is controlled to open to determine whether or not exhaust gas recirculation through the exhaust gas recirculation passage 11 is being performed (EGR = ON). EG
When the R control valve 12 is closed and the exhaust gas recirculation passage 11 is shut off (or adjusted to the reference minimum opening degree), the routine proceeds to step 3, where the throttle valve opening degree TVO and the engine rotation speed Ne. With respect to the Q map for storing the intake air amount Q for each of the operation regions previously divided into
The intake air amount Q read in step 1 is updated and stored.

Specifically, on the Q map, an operating region to which the current throttle valve opening TVO and the engine rotation speed Ne correspond is specified, and the intake air amount Q is stored in the specified operating region. At this time, the stored intake air amount Q and the latest detected intake air amount Q are weighted averaged, and the weighted average value is newly stored in the operating region, and the weighted average value is stored in the specified operating region. When the intake air amount Q is not stored, the latest detected Q is stored as it is as the data of the corresponding area.

Here, the volume flow rate of the intake air in the engine 1 can be obtained by the engine rotation speed Ne and the throttle valve opening TVO, but since the volume flow rate is not affected by the presence or absence of exhaust gas recirculation, the engine rotation speed is Speed Ne
If the detection Q as the mass flow rate is stored for each operating region divided by the throttle valve opening TVO and the throttle valve opening TVO, the change in the mass flow rate due to the exhaust gas recirculation can be correctly captured.

On the other hand, when it is determined in step 2 that the EGR control valve 12 is controlled to be opened to a predetermined opening degree and exhaust gas recirculation is being performed through the exhaust gas recirculation passage 11, the Q map is referred to. Then, when exhaust gas recirculation is not performed under the same operating conditions, the intake air amount Q detected by the hot wire air flow meter 14 is read. Here, when the intake air amount Q is not stored in the operating region where the current throttle valve opening TVO and the engine rotation speed Ne correspond, that is, when the operating region is not experienced in the exhaust gas recirculation shutoff state. Reads the intake air amount Q stored in the operating region preset as a region in which the intake air amount Q is substantially the same as that of the corresponding operating region.

That is, in the operating region divided into a plurality of throttle valve opening TVO and engine speed Ne, as shown in FIG. 5, the rotational speed increases as the throttle valve opening TVO increases with respect to a certain operating region. There is an operating region in which the substantially same intake air amount Q is obtained in the direction in which the speed Ne decreases. Therefore, when the intake air amount Q is not stored in the relevant operating region, the intake air amount Q is stored by reading the storage data of another region where the substantially same intake air amount Q should be obtained. Even in an operating region where the exhaust gas recirculation is not performed, the exhaust gas recirculation correction control described later can be performed.

When the intake air amount Q is not stored in the relevant operating region and the stored data of another operating region which is preset as the intake air amount Q being substantially equal is read out, the intake air amount Q is read. It is also possible to read the stored data of the operating region closest to the relevant region among other stored regions, or to calculate the average value of the stored data of the other operating regions.

In step 5, the intake air amount Q is not stored in the corresponding area on the Q map, and the intake air amount Q is also sucked in other areas preset as the area where the same air amount Q is obtained. Whether or not the air amount Q is not stored, in other words, when the exhaust gas recirculation is cut off under the current operating conditions, the intake air amount Q detected by the air flow meter 14 is calculated from the Q map. It is determined whether or not the data cannot be read.

When it is determined in step 5 that the data of the intake air amount Q cannot be read out, the learning correction described later cannot be performed, and thus this routine is ended. On the other hand, in step 5, the intake air amount Q data is Q
If it is determined that it is obtained from the map, step 6
Then, the flow advances to and the obtained data of the intake air amount Q is set in Qφ as the data corresponding to the cutoff state of the exhaust gas recirculation.

Then, in step 7, the intake air amount Q detected by the hot-wire air flow meter 14 in the current state where the exhaust gas recirculation is being performed and the same operating condition when the exhaust gas recirculation is cut off obtained from the Q map are performed. Obtained intake air amount Q
Based on φ, the actual exhaust gas recirculation rate ER is calculated according to the following equation. ER = (Qφ-Q) / Qφ That is, when exhaust gas recirculation is performed, the fresh air inflow air amount (mass flow rate) detected by the hot-wire air flow meter 14 decreases by the exhaust gas recirculation amount ( 6), the deviation between the intake air amount Qφ detected when the exhaust gas recirculation is cut off under the same operating conditions and the intake air amount Q detected when the exhaust gas recirculation is performed (= Qφ−Q ) Corresponds to the exhaust gas recirculation amount. Then, the exhaust gas recirculation amount is calculated as the actual intake air amount (air flow meter 14
Is the detected Q of the fresh air inflow air amount + exhaust gas recirculation amount (Qφ-
The value obtained by dividing the intake air amount Qφ, which is Q)), indicates the current actual exhaust gas recirculation rate ER.

In step 8, the map in which the required exhaust gas recirculation rate ERφ is stored in advance for each operating region divided by the basic fuel injection amount Tp corresponding to the engine load and the engine rotation speed Ne is referred to and the current operating conditions are set. Corresponding required exhaust gas recirculation rate ER
Read φ. In step 9, the required exhaust gas recirculation rate E
The correlation map between Rφ and the actual exhaust gas recirculation rate ER is corrected.

In the initial matching state, the required exhaust gas recirculation rate ERφ is converted into a control pulse (control amount) to be given to the step motor of the EGR control valve 12 to adjust the opening degree of the EGR control valve 12, so that Since the required exhaust gas recirculation rate ERφ is set, the required exhaust gas recirculation rate ER is set.
The initial value of the correlation map between φ and the actual exhaust gas recirculation rate ER is E
Given as Rφ = ER.

Here, when the exhaust gas recirculation amount obtained for the control pulse in the initial state decreases due to dirt on the valve body of the EGR control valve 12 or the like (see FIG. 8), the actual exhaust gas recirculation ratio ERφ is exceeded. The exhaust gas recirculation rate ER of
The relationship of ERφ = ER will be broken. Therefore, in step 9, a process of correcting the correlation map of the required exhaust gas recirculation rate ERφ and the actual exhaust gas recirculation rate ER is performed to match the actual situation. Specifically, the actual exhaust gas recirculation rate ER calculated this time (or the weighted average value of the ER previously set to correspond to ERφ and the ER newly calculated this time) is set to the ERφ concerned. Corresponding E
Update and set as R data. The required exhaust gas recirculation rate E
It is advisable to correct not only the ER data corresponding to the corresponding ERφ but also the preceding and following data so that the ER data changes smoothly with respect to the change in Rφ.

As described above, the required exhaust gas recirculation rate ER
The correlation map between φ and the actual exhaust gas recirculation rate ER was corrected to match the actual power at that time, and the correction map is shown in FIG.
Even if the correlation between the required exhaust gas recirculation rate ERφ and the actual exhaust gas recirculation rate ER changes from the initial state, the exhaust gas recirculation rate required for each operating condition can be maintained by referring to the flowchart in FIG.

In the flowchart of FIG. 4, first, in step 11, the map is stored in advance, which stores the required exhaust gas recirculation rate ERφ according to the basic fuel injection amount Tp (engine load) and the engine speed Ne. The exhaust gas recirculation rate ERφ required according to the conditions is obtained. In the next step 12, the correlation map between the required exhaust gas recirculation rate ERφ and the actual exhaust gas recirculation rate ER corrected in step 9 of the flow chart of FIG. 3 is referred to. At this time, the required exhaust gas recirculation rate obtained in step 11 is referred to. Assuming that the rate ERφ is the actual exhaust gas recirculation rate ER in the correlation map, the required exhaust gas recirculation rate ERφ corresponding to the required exhaust gas recirculation rate ERφ obtained in step 11 is obtained from the correlation map.

For example, when the exhaust gas recirculation amount decreases as compared with the initial state due to the contamination of the valve body of the EGR control valve 12, the actual exhaust gas recirculation ratio ER corresponding to the required exhaust gas recirculation ratio ERφ in the above correlation map becomes greater. It will be modified slightly. This is seen from the actual exhaust gas recirculation rate ER side,
The corresponding required exhaust gas recirculation rate ERφ will be corrected to a higher value (see FIG. 7).

Since it is desired to actually obtain the required exhaust gas recirculation ratio ERφ obtained in step 11, the recirculation ratio E is required.
When Rφ is the actual recirculation rate ER, the corresponding required exhaust gas recirculation rate ERφ on the correlation map becomes the recirculation rate ERφ that should be the target in control, and the target recirculation rate E higher than the actual request.
By setting Rφ, the initial exhaust gas recirculation rate is ensured by compensating for the decrease in the opening area due to the contamination.

When the required exhaust gas recirculation rate ERφ is converted in step 12, in step 13, a conversion table set in advance for converting the required exhaust gas recirculation rate ERφ into a control pulse (control amount) is used. Required exhaust gas recirculation rate ERφ
Is obtained and the control pulse is output to the step motor of the EGR control valve 12. As described above, in the present embodiment, the exhaust gas recirculation rate ERφ required from the engine operating conditions is corrected by the conversion using the correlation map in step 12, resulting in the control pulse (control amount).
Is corrected in accordance with the correlation change between the required exhaust gas recirculation rate ERφ and the actual exhaust gas recirculation rate ER.

In the above embodiment, the intake air amount Q detected by the hot-wire air flow meter 14 when the exhaust gas recirculation is cut off is determined by the throttle valve opening TVO and the engine speed N.
Although it is stored for each operation region divided into a plurality of parts by e and e, in a system including a sensor for detecting the intake pipe pressure (intake negative pressure), the intake pipe pressure (intake pipe) is changed instead of the throttle valve opening TVO. Negative pressure) may be used.

Further, the EGR control valve 12 in the above embodiment
Shows that it is driven by a step motor, but it may be a valve having a configuration in which the magnetic attraction force of the linear solenoid is duty controlled. Further, in the above embodiment, the required exhaust gas recirculation ratio before being converted into the control amount is set to be corrected, but it is clear that the conversion table of the required exhaust gas recirculation ratio and the control amount may be corrected. Is.

[0045]

As described above, according to the exhaust gas recirculation control device of the invention of claim 1, the actual exhaust gas recirculation amount is detected by utilizing the characteristic that the fresh air inflow air amount is reduced by the exhaust gas recirculation. Since the control amount is corrected so that the desired exhaust gas recirculation amount (recirculation ratio) is achieved, even if the opening area corresponding to the control amount changes due to valve contamination, etc., the desired exhaust gas recirculation amount (recirculation ratio) ) Can be maintained.

According to the exhaust gas recirculation control device of the second or third aspect of the invention, there is an effect that only the change in the mass flow rate due to the presence or absence of exhaust gas recirculation can be accurately captured.
According to the exhaust gas recirculation control device of the fourth aspect of the present invention, since the actual exhaust gas recirculation ratio is calculated, the control amount corresponding to the required exhaust gas recirculation ratio can be obtained correctly.

According to the exhaust gas recirculation control device of the fifth aspect of the present invention, even under the condition corresponding to the operating region where the intake air amount could not be stored in the state where the exhaust gas recirculation was cut off, There is an effect that it is possible to correct the control amount using the stored data in the operation region of 1, and to secure an opportunity for correction control.

[Brief description of drawings]

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

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

FIG. 3 is a flowchart showing a control amount correction control of the embodiment.

FIG. 4 is a flowchart showing correction control of a control amount according to the embodiment.

FIG. 5 is a diagram showing a characteristic of air amount on a map for storing an intake air amount.

FIG. 6 is a time chart showing how the intake air amount changes with and without exhaust gas recirculation.

FIG. 7 is a diagram showing a correction characteristic of a control amount in the embodiment.

FIG. 8 is a diagram showing how the exhaust gas recirculation amount changes due to valve contamination.

[Explanation of symbols]

 1 Internal Combustion Engine 4 Intake Manifold 5 Throttle Valve 6 Fuel Injection Valve 10 Exhaust Manifold 11 Exhaust Gas Recirculation Path 12 EGR Control Valve 13 Control Unit 14 Hot-Wire Air Flow Meter 15 Throttle Sensor 16 Crank Angle Sensor

Claims (5)

[Claims] 1. Exhaust gas recirculation control means for controlling an exhaust gas recirculation amount for recirculating a part of engine exhaust gas to an engine intake system, and intake air amount detection means for directly detecting an intake air amount of an engine as a mass flow rate. Intake air amount storage means for updating and storing the intake air amount detected by the intake air amount detection means in each of a plurality of operating regions in a state where the exhaust gas recirculation control means shuts off the exhaust gas recirculation; The exhaust gas recirculation is performed based on the intake air amount detected by the intake air amount detection means and the intake air amount stored in the intake air amount storage means while the exhaust gas recirculation is being performed by the recirculation control means. An exhaust gas recirculation control device for an internal combustion engine, comprising: a control amount correction unit that corrects a control amount of exhaust gas recirculation by the control unit. 2. The intake air amount storage means stores the intake air amount for each operation region divided into a plurality of sections according to the engine speed and the throttle valve opening.
An exhaust gas recirculation control device for an internal combustion engine as described. 3. The internal combustion engine according to claim 1, wherein the intake air amount storage means stores the intake air amount for each of operating regions divided into a plurality of regions according to the engine speed and the intake negative pressure. Exhaust gas recirculation control device. 4. The control amount correction means stores the intake air amount detected by the intake air amount detection means in a state where the exhaust gas recirculation control means is performing exhaust gas recirculation, and the intake air amount storage means. An exhaust gas recirculation ratio calculation means for calculating an exhaust gas recirculation ratio based on the intake air amount that has been set, and a required exhaust gas recirculation ratio preset based on the exhaust gas recirculation ratio calculated by the exhaust gas recirculation ratio calculation means and the engine operating state. 4. The control characteristic correction means for correcting the correlation between the required exhaust gas recirculation rate and the control amount based on the difference between Exhaust gas recirculation control device for internal combustion engine. 5. The control amount correction means is preset as an operation region in which the intake air amount becomes substantially the same as the corresponding operation region at that time in the operation region divided into a plurality in the intake air amount storage means. The exhaust gas recirculation control device for an internal combustion engine according to claim 1, wherein the control amount is corrected by using an intake air amount stored in any one of the operating regions.