JP4228953B2 - Control device for internal combustion engine - Google Patents

Description

  The present invention relates to a control device for an internal combustion engine including a variable capacity turbocharger and an EGR device.

  2. Description of the Related Art In a turbocharger that drives an exhaust turbine with exhaust gas from an engine and supercharges intake air, a variable displacement turbocharger is known in which a variable nozzle is provided at the inlet of the exhaust turbine so that the exhaust flow rate can be changed. For example, by reducing the opening area of the variable nozzle, the exhaust flow rate can be increased and the rotation speed of the exhaust turbine can be kept high, so the supercharging pressure can be arbitrarily controlled so as to be the optimum value according to the operating state of the engine Is possible.

  On the other hand, in order to reduce NOx contained in the exhaust gas, an EGR device that recirculates a part of the exhaust gas to the intake passage is installed. The EGR device suppresses NOx generation by reducing the engine combustion temperature by the exhaust gas returned to the intake air through the EGR passage, and changes the opening of the EGR valve provided in the EGR passage according to the operating state of the engine. The amount of EGR is controlled.

  Here, the supercharging pressure and the EGR amount of the variable capacity turbocharger are generally feedback-controlled so that the detection values by the sensors or the like follow the target values. However, the supercharging pressure and the EGR amount are correlated with each other, and when the opening of the variable nozzle is changed, the exhaust pressure changes, and the EGR amount passing through the EGR valve varies. For this reason, they affect each other, and in particular, during transient operation such as acceleration or deceleration, there is a concern that controllability will be reduced due to operation delay and exhaust emission will be temporarily deteriorated.

  FIG. 9A shows an example in which EGR control is performed without cooperation with supercharging pressure control in a system in which supercharging pressure control and EGR control using a variable nozzle turbocharger coexist. For example, when the vane of the variable nozzle is suddenly closed so as to follow the target boost pressure that rapidly increases during acceleration, the actual EGR rate varies greatly as shown in the figure. That is, the exhaust gas inflow amount to the exhaust turbine is rapidly reduced, so that the exhaust pressure increases, and as a result, the EGR gas amount (actual EGR rate) increases. On the other hand, in EGR control, the EGR valve is feedback controlled to correct this increase in order to match the actual EGR rate to the target EGR rate. However, since there is a delay in the flow of the supply and exhaust gas, it takes time to converge. In short, accurate EGR rate control becomes difficult.

For this reason, integrating and controlling supercharging pressure control and EGR amount control has been studied (Patent Documents 1 to 6). For example, the control amount of the variable nozzle is corrected corresponding to the correction amount of the target EGR rate (Patent Document 1), or during the transient operation, the variable nozzle and the EGR valve are not operated simultaneously, and the control of the other is performed after the start of one control. (Patent Documents 2 and 3) are known.
JP 2000-002122 A Japanese Patent Laid-Open No. 10-231730 JP 2002-227705 A

Therefore, in order to consider the influence of the turbocharger during EGR control, a method of performing EGR control by estimating the EGR amount according to the differential pressure between the exhaust pressure and the intake pipe pressure calculated based on the operating state is proposed. (Patent Document 4). In addition to the method of performing the control based on the estimated value, the actual EGR flow rate is calculated using a physical model to reduce the response delay of the EGR flow rate and the influence of the turbo lag (Patent Document 5). Various proposals have been made such as estimating exhaust pressure based on engine load, intake air amount, and exhaust temperature, and performing variable nozzle / EGR valve control based on the estimated value (Patent Document 6).
JP 09-021340 A JP 2001-003796 A JP 2000-356158 A

  However, in the control methods of Patent Documents 1 to 3, although the variable nozzle and the EGR valve are not subjected to feedback control at the same time, deterioration of controllability is avoided, but response delay cannot be eliminated. Moreover, in the control method which controls based on an estimated value like patent documents 4-6, a calculation becomes complicated in order to improve estimation accuracy, or control accuracy falls, when it is going to improve responsiveness, etc. It was not enough for practical use.

  Therefore, an object of the present invention is to achieve both the supercharging pressure control and the EGR control with a simple control method, to quickly achieve the target supercharging pressure during transient operation, and to suppress the EGR fluctuation accompanying the supercharging pressure change. The goal is to converge to the target EGR rate with good responsiveness.

In order to achieve the above object, in the invention of claim 1 of the present application,
In a control device for an internal combustion engine comprising a variable capacity turbocharger that drives an exhaust turbine having a variable nozzle to supercharge intake air, and an EGR device that recirculates part of the exhaust gas to intake air in an EGR passage having an EGR valve,

Target boost pressure calculating means for calculating the target boost pressure of the variable capacity turbocharger based on the operating state of the internal combustion engine;
An actual boost pressure detecting means for detecting the actual boost pressure;
A nozzle opening that feedback-controls the opening of the variable nozzle so that the actual boost pressure detected by the actual boost pressure detecting means follows the target boost pressure calculated by the target boost pressure calculating means. A degree control means was provided. The nozzle opening control means includes
Transient determining means for determining whether the operating state of the internal combustion engine is a transient operating state;
Feedback amount calculation means for calculating a feedback amount based on the deviation between the actual boost pressure and the target boost pressure;
And a transient correction unit that corrects the feedback amount so that the feedback gain by the feedback amount calculation unit is smaller than that during steady operation when the transient determination unit determines that the operation state is transient .
Further, the transient correction means is provided with a correction coefficient calculation means for calculating a correction coefficient for the feedback amount, and the correction coefficient calculation means increases the correction coefficient with time using the initial value immediately after the transient determination as a lower limit value, and performs steady operation. It was set as the structure which returned to the correction coefficient of time.

  The nozzle opening control means of claim 1 controls the variable nozzle opening of the variable capacity turbocharger by correcting the feedback amount so that the feedback gain becomes smaller than that in the steady operation when the transient determination is made. That is, since the change in the variable nozzle opening becomes small, a rapid increase in the exhaust pressure can be suppressed, and the increase in the EGR amount can be suppressed accordingly. As a result, it is possible to control to a desired EGR rate without largely changing the EGR valve opening in order to correct the increase in the EGR amount. Further, even if the movement of the variable nozzle opening is made small, there is a time delay in increasing the supercharging pressure, so the influence on the controllability of the supercharging pressure is small. Therefore, it is possible to achieve both supercharging pressure control and EGR control with a simple control method.

  The correction coefficient calculation means limits the movement of the variable nozzle at the initial stage of acceleration by sufficiently reducing the feedback gain immediately after the transient determination. Thereby, it is possible to suppress a rapid increase in the exhaust gas pressure and suppress a rapid increase in the EGR amount. Thereafter, by increasing the correction coefficient at regular intervals, the target supercharging pressure can be quickly realized, and the influence on the EGR control can be reduced to realize accurate EGR control.

In the invention of claim 2, the nozzle opening control means is
Basic nozzle opening calculating means for calculating the basic opening of the variable nozzle based on the operating state of the internal combustion engine;
There is provided target nozzle opening calculating means for calculating the target nozzle opening by adding the feedback amount calculated by the feedback amount calculating means to the basic nozzle opening calculated by the basic nozzle opening calculating means.

  The nozzle opening control means preferably calculates the basic opening of the variable nozzle according to the operating state, and calculates the target nozzle opening obtained by adding the feedback amount thereto. During transient operation, the feedback amount is corrected by the transient correction means, so that the movement of the variable nozzle can be quickly limited, and the supercharging pressure and the EGR rate can be controlled with good controllability.

In the invention of claim 3 , the control device for the internal combustion engine comprises:
Target intake air amount calculating means for calculating a target intake air amount based on the operating state of the internal combustion engine;
An actual intake air amount detecting means for detecting the actual intake air amount;
Valve opening control means for feedback-controlling the EGR valve opening is provided so that the actual intake air amount detected by the actual intake air amount detecting means follows the target intake air amount calculated by the target intake air amount calculating means. .

  The EGR control is feedback controlled by the valve opening control means based on the target intake air amount and the actual intake air amount according to the operating state. If the variable nozzle opening control of the present invention described above is performed, the amount of EGR gas does not fluctuate greatly at the time of transition, so that it is not necessary to perform correction or control in consideration of exhaust pressure. Accurate EGR control with high responsiveness is possible by normal feedback control.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a schematic configuration of a control device in which the present invention is applied to a diesel engine.

  In FIG. 1, reference numeral 1 denotes a diesel engine main body, which injects fuel from an injector 2 disposed in each cylinder of the engine 1 into a combustion chamber 1a. The injector 2 is connected to a common rail that accumulates high-pressure fuel by a fuel supply passage (not shown). An intake passage 3 is connected to the intake port of the combustion chamber 1a. The intake passage 3 includes an air flow meter 4 for detecting the intake air amount as an actual intake air amount detecting means, and a variable capacity turbocharger for supercharging the intake air. An intake air pressure sensor 7 and an intake air temperature sensor 8 for detecting intake air pressure (supercharging pressure) are provided as an intake air compressor 5A, an intake throttle valve 6, and actual supercharging pressure detection means. An exhaust passage 9 following the exhaust port of the combustion chamber 1a is provided with an exhaust turbine 5B of a variable capacity turbocharger and an oxygen sensor 11 for detecting the oxygen concentration in the exhaust. An EGR valve 13 is provided in the EGR passage 12 that connects the exhaust passage 9 upstream of the exhaust turbine 5B and the intake passage 3 downstream of the intake throttle valve 6 to constitute an EGR device (exhaust gas recirculation device). .

  The variable capacity turbocharger has a known structure and compresses intake air by coaxially connecting an intake compressor 5A to an exhaust turbine 5B driven to rotate by exhaust gas. The exhaust turbine 5B has a variable nozzle (not shown) for adjusting the introduction exhaust flow velocity, and controls the vane position of the variable nozzle so that a predetermined supercharging pressure corresponding to the operating state of the engine 1 is obtained. To do. The vanes of the variable nozzle are driven by, for example, an electromagnetically driven actuator, and are controlled according to a signal from the ECU (electronic control unit) 10. For example, the ECU 10 controls the nozzle opening to the closed side in order to increase the flow rate of the exhaust gas introduced into the exhaust turbine 5B in the low engine speed range, and introduces the exhaust gas into the exhaust turbine 5B without resistance in the high speed range. Therefore, the nozzle opening is controlled to the open side.

  The EGR device lowers the combustion temperature by the exhaust gas recirculated to the intake passage 3 and suppresses the generation of NOx. The EGR valve 13 is driven by an electromagnetically driven actuator connected to the ECU 10 and controls the recirculation amount of the exhaust gas by adjusting the valve position so that a predetermined EGR rate corresponding to the operating state of the engine 1 is obtained. . Further, in order to detect the operating state, the engine 1 includes a rotation speed sensor 15 that outputs a signal corresponding to the engine speed, an accelerator opening sensor 14 that outputs a signal corresponding to the accelerator pedal position, and engine cooling water. A water temperature sensor 16 and the like for outputting a signal corresponding to the temperature of the engine are disposed, and the air flow meter 4, the intake pressure sensor 7, the intake temperature sensor 8, the oxygen sensor 11 and the like described above are connected to the ECU 10 respectively. Has been.

  The ECU 10 has a known configuration including an input / output port (not shown), a storage device such as a ROM and a RAM, a central processing unit (CPU), a timer counter, etc., and a supercharging pressure control by a variable capacity turbocharger and an EGR control by an EGR device. Various control of the engine 1 including is comprehensively performed. Detection results from the various sensors are input to the input port of the ECU 10, and the ECU 10 determines a fuel injection amount, an injection timing, and the like based on the detection results, outputs a drive signal for the injector 2, etc. The nozzle opening degree and EGR amount of the turbine 5B are determined, and driving of an actuator or the like for adjusting the variable nozzle vane position or the valve position of the EGR valve 13 is controlled.

  Next, the supercharging pressure control and the EGR control performed by the ECU 10 will be described in detail with reference to the drawings. 2 to 6 are diagrams showing variable nozzle vane position control in the variable displacement turbocharger, and FIGS. 7 and 8 are diagrams showing EGR valve position control in the EGR device.

  In a system in which supercharging pressure control by a variable capacity turbocharger and EGR control coexist, when feedback control by normal PID (proportional / integral / differential compensation) control is performed, as shown in FIG. During acceleration, the vanes of the variable nozzle are abruptly closed so as to follow the target supercharging pressure. Then, the exhaust amount flowing into the exhaust turbine 5B decreases, the exhaust pressure increases, and the EGR gas amount increases accordingly. On the other hand, the EGR control controls the EGR valve so as to correct the increase in the EGR gas amount in order to match the target EGR rate. However, since the flow of the supply / exhaust gas is delayed, accurate EGR rate control becomes difficult. Therefore, in the present invention, the correction coefficient is set so that the gain amount in the transient state of the boost pressure control that is feedback-controlled is smaller than that in the steady operation.

  FIG. 2 is a block diagram of variable nozzle vane position control according to the present invention. The ECU 10 calculates the target boost pressure according to the engine speed and the target injection amount (operation state) (target boost pressure calculating means). On the other hand, the basic vane position is calculated from the basic vane position characteristics of the variable nozzle determined according to the operating state of the engine 1 (basic nozzle opening calculation means). Then, a PID control amount is calculated based on the deviation between the calculated target boost pressure and the actual boost pressure measured by the intake pressure sensor (actual boost pressure detecting means) 7 (feedback amount calculating means), This is added to the basic vane position to calculate the target vane position (target nozzle opening calculation means) and control the vane position of the variable nozzle (nozzle opening control means).

  Further, in the present invention, when calculating the PID control amount, it is determined whether or not the engine 1 is in a transient operation state (transient determination means), and when the transient determination is made, the gain of PID control is made smaller than that during steady operation. The transient gain correction coefficient is calculated (correction coefficient calculation means) to correct the PID control amount (transient correction means). As described above, the influence on the EGR control can be reduced by correcting the decrease in the PID control amount at the time of transition and limiting the movement of the variable nozzle vane. Here, for example, as shown in FIG. 3, the correction coefficient for limiting the movement of the variable nozzle vanes is preferably increased with time after the transient determination, and the restriction is released. Specifically, the correction coefficient initial value immediately after the transient determination is set to 0 (lower limit value), and the correction coefficient is increased with time until the correction coefficient becomes 1 (upper limit value).

  FIG. 4 is a control routine for calculating the target vane position of the variable nozzle according to the present invention, and is executed at a predetermined calculation cycle. In step 101, first, the engine speed and the target fuel injection amount are read, and the target boost pressure is calculated from map data stored in advance. The engine speed can be calculated from the output of the speed sensor 15, and the target fuel injection amount can be calculated based on the engine speed and the output of the accelerator opening sensor 14 in a separately executed fuel injection control routine.

  In step 102, the basic vane position of the variable nozzle is calculated from map data stored in advance based on the read engine speed and target fuel injection amount. In step 103, the actual boost pressure detected by the intake pressure sensor 7 is read, the actual boost pressure is subtracted from the target boost pressure calculated in step 101, and the deviation is calculated.

  In step 104, it is determined whether or not the operating state of the engine 1 is in a transient state. The transient determination means determines that the state is a transient state when, for example, the difference between the previous value and the current value of the accelerator pedal position by the accelerator opening sensor 14 is a predetermined value or more. Alternatively, when the difference between the previous value and the current value of the target injection amount is greater than or equal to a predetermined value, it may be determined as a transient state.

  If it is determined in step 104 that the state is not in a transient state, the process proceeds to step 105, the value of the gain correction coefficient at the time of transition is set to 1, and the process proceeds to step 107. As a result, when not in a transient state, gain correction is not substantially performed. If it is determined in step 104 that the state is a transient state, the process proceeds to step 106, and a transient gain correction coefficient is calculated. This is to reduce the change in the EGR amount by reducing the change in the vane position during the transition, and is set so that the correction coefficient increases with time as shown in FIG. The correction coefficient calculation method will be described with reference to FIG.

  In step 201 of FIG. 5, it is determined whether or not the transient determination is made for the first time. For example, the previous value of the transient determination result in step 104 of FIG. 4 is compared with the current value, and when it is determined that the current state is in the transient state for the first time, the process proceeds to step 202 to calculate the correction coefficient initial value. The initial value of the correction coefficient is, for example, 0 from FIG. 3 described above, and this initial value is set as the current correction coefficient in step 204. In step 201, if the previous transition was also in a transitional state, the process proceeds to step 203, where a predetermined correction coefficient increment is added to the previous correction coefficient, and in step 204, this added value is used as the current correction coefficient.

In step 107 of FIG. 4, the feedback amount is calculated by PID control based on the deviation between the target boost pressure calculated in step 103 and the actual boost pressure. The PID control amount is represented by a proportional correction amount, a differential correction amount, and an integral correction amount as in the following equation, and is calculated by multiplying these correction amounts by the correction coefficients calculated in steps 105 and 106 and adding them. .
PID control amount = (VNT_FbP + VNT_FbD) * K + VNT_FbI
In the equation, VNT_FbP: proportional correction amount, VNT_FbD: differential correction amount, VNT_FbI: integral correction amount, K: correction coefficient Here, since the integral correction amount is very small, the integral correction amount is multiplied by the correction coefficient K in the above equation. Of course, an equation obtained by multiplying the integral correction amount by the correction coefficient may be used.

In step 108, the target vane position is calculated by adding the PID control amount calculated in step 107 to the basic vane position calculated in step 102. This calculation formula is shown as follows, for example.
VNT_Fin = VNT_Base + [(VNT_FbP + VNT_FbD) * K + VNT_FbI]
VNT_Fin: target vane position, VNT_Base: basic vane position,

  Thus, when the engine operating state is in a transient state, the movement of the variable nozzle vane can be limited by performing the gain correction using the correction coefficient. This will be described with reference to FIG. FIG. 6 (a) shows the change in the vane actual position during the transition according to the conventional method. When the target supercharging pressure suddenly rises during acceleration, feedback control is performed to follow this, and the vane of the variable nozzle suddenly increases. Closed. On the other hand, in the control method of the present invention shown in FIG. 6B, since the feedback gain at the time of transition is corrected so as to be sufficiently small, the change in the vane actual position becomes small. For this reason, the amount of exhaust gas flowing into the exhaust turbine 5B does not decrease rapidly, and the change in exhaust pressure is suppressed. Therefore, even if normal EGR control is performed, the influence on the EGR gas amount is small.

  FIG. 7 is a block diagram of EGR control in the EGR device, and the ECU 10 calculates the target intake air amount according to the operation state such as the rotational speed of the engine 1 and the target injection amount (target intake air amount calculating means). On the other hand, the basic EGR valve position is calculated from the basic EGR valve position characteristic determined according to the operating state of the engine 1. Then, a PID control amount is calculated based on the deviation between the calculated target intake air amount and the actual intake air amount actually measured by the air flow meter (intake air amount detecting means) 4, and is added to the basic EGR valve position to be added to the target EGR valve. The position is calculated and the EGR valve 13 is controlled (valve opening control means).

  FIG. 8 is a control routine for calculating the target EGR valve position according to the present invention, and is executed at a predetermined calculation cycle. In step 301, first, the engine speed and the target fuel injection amount are read, and the target intake air amount is calculated from map data stored in advance. The engine speed is calculated from the output of the speed sensor 15, and the target fuel injection amount is calculated based on the engine speed and the output of the accelerator opening sensor 14 in another control routine.

  In step 302, the basic EGR valve position is calculated from map data stored in advance based on the read engine speed and target fuel injection amount. In step 303, the actual intake air amount detected by the air flow meter 4 is read, the actual intake air amount is subtracted from the target intake air amount calculated in step 301, and the deviation is calculated. In step 304, based on the deviation between the target intake air amount and the actual intake air amount calculated in step 303, a feedback amount by normal PID control is calculated. In step 305, the target EGR valve position is calculated by adding the PID control amount calculated in step 304 to the basic EGR valve position calculated in step 302.

  FIG. 9 shows changes in the target EGR rate and the EGR valve position accompanying the change in the supercharging pressure during the transition shown in FIG. In the conventional method of FIG. 9A, the vane of the variable nozzle is abruptly closed during the transition as described above, and the exhaust pressure rises, so that the actual EGR rate exceeds the target EGR rate and is suppressed. The EGR valve position varies. On the other hand, according to the control method of the present invention shown in FIG. 9B, since the change in the vane actual position at the time of transition is small, the EGR amount does not increase as in the prior art, and the fluctuation of the EGR valve position can be prevented.

  Thus, according to the present invention, a rapid increase in exhaust pressure can be suppressed by restricting the movement of the variable nozzle vane during transient operation, particularly in the early stage of acceleration. This makes it possible to control the desired EGR rate without increasing the movement of the EGR valve. Therefore, stable control can be performed with high accuracy without requiring complicated control and apparatus, and both supercharging pressure control of the variable capacity charger and EGR control by the EGR apparatus can be achieved.

  In the present invention, there is a concern that the follow-up delay of the supercharging pressure is limited by restricting the movement of the vanes of the variable nozzle in the early stage of acceleration, but the exhaust energy increases from the start of acceleration, thereby increasing the rotation of the turbo. There is a considerable delay before the boost pressure rises. Therefore, as shown in FIGS. 6A and 6B, it is not so affected. However, it is not desirable to suppress the movement of the vanes using a time correction factor that is long enough to be affected.

  The present invention is applicable to any internal combustion engine provided with a variable capacity turbocharger and an EGR device. In the above embodiment, the example applied to a diesel engine has been described, but other internal combustion engines may be used. . The configurations of the variable capacity turbocharger and the EGR device are not limited to the configurations described in the above embodiment, and may be other known configurations.

It is a basic system figure of the control device of the diesel engine in the 1st embodiment of the present invention. It is a block diagram of variable nozzle vane position control of the variable capacity turbocharger by ECU. It is a flowchart figure which shows the control routine of a variable nozzle vane position. It is a flowchart figure which shows the calculation routine of the gain correction coefficient at the time of a transition. It is a figure for demonstrating the calculation method of the gain correction coefficient at the time of a transition. (A) is a figure which shows the mode of the actual supercharging pressure change at the time of the transition by the conventional control method, (b) is a figure which shows the mode of the actual supercharging pressure change at the time of the transition by the control method of this invention. It is a block diagram of EGR control in the EGR device by ECU. It is a flowchart figure which shows the EGR control routine of the EGR apparatus by ECU. 2A and 2B are diagrams for explaining the effect of the present invention, in which FIG. 1A shows a state of changes in actual supercharging pressure and actual EGR amount during a transition by the conventional control method, and FIG. 2B shows a transient by the control method of the present invention. It is a figure which shows the mode of the actual supercharging pressure and the actual EGR amount change at the time.

Explanation of symbols

1 Diesel engine (internal combustion engine)
2 Injector 3 Air intake passage 4 Air flow meter (actual intake air amount detection means)
5A Intake compressor 5B Exhaust turbine 6 Intake throttle valve 7 Intake pressure sensor (actual boost pressure detection means)
8 Intake air temperature sensor 9 Exhaust passage 10 Electronic control unit (ECU)
11 Oxygen sensor 12 EGR passage 13 EGR valve 14 Accelerator opening sensor 15 Speed sensor 16 Water temperature sensor

Claims (3)

A control device for an internal combustion engine, comprising: a variable capacity turbocharger that drives an exhaust turbine having a variable nozzle to supercharge intake air; and an EGR device that recirculates part of the exhaust gas to intake air through an EGR passage having an EGR valve. ,
Target boost pressure calculating means for calculating the target boost pressure of the variable capacity turbocharger based on the operating state of the internal combustion engine;
An actual boost pressure detecting means for detecting the actual boost pressure;
A nozzle opening that feedback-controls the opening of the variable nozzle so that the actual boost pressure detected by the actual boost pressure detecting means follows the target boost pressure calculated by the target boost pressure calculating means. Degree control means, the nozzle opening control means,
Transient determining means for determining whether the operating state of the internal combustion engine is a transient operating state;
Feedback amount calculation means for calculating a feedback amount based on the deviation between the actual boost pressure and the target boost pressure;
A transient correction unit that corrects the feedback amount so that the feedback gain by the feedback amount calculation unit becomes smaller than that during steady operation when the transient determination unit determines that the operation state is transient ;
The transient correction means includes a correction coefficient calculation means for calculating a correction coefficient for the feedback amount, and the correction coefficient calculation means increases the correction coefficient with time using the initial value immediately after the transient determination as a lower limit value, and performs steady operation. A control apparatus for an internal combustion engine, wherein the control coefficient is restored to the correction coefficient for the hour . The nozzle opening control means is
Basic nozzle opening calculating means for calculating the basic opening of the variable nozzle based on the operating state of the internal combustion engine;
The target nozzle opening calculating means for calculating the target nozzle opening by adding the feedback amount calculated by the feedback amount calculating means to the basic nozzle opening calculated by the basic nozzle opening calculating means. The control apparatus for an internal combustion engine according to claim 1 . Target intake air amount calculating means for calculating a target intake air amount based on the operating state of the internal combustion engine;
An actual intake air amount detecting means for detecting the actual intake air amount;
Valve opening control means for feedback-controlling the EGR valve opening is provided so that the actual intake air amount detected by the actual intake air amount detecting means follows the target intake air amount calculated by the target intake air amount calculating means. The control apparatus for an internal combustion engine according to claim 1 or 2 .

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