JP3704726B2 - Control device for internal combustion engine - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a control device for an internal combustion engine, and more particularly to a technique for appropriately controlling a fuel supply amount and ignition timing in an engine equipped with an exhaust gas recirculation device.
[0002]
[Prior art]
Conventionally, an exhaust gas recirculation device is known as a device for reducing the NOx emission amount from the engine. At the same time, the exhaust gas recirculation changes the charging efficiency of the engine, thereby deteriorating the accuracy of fuel injection control. It is known.
As a technique for avoiding the deterioration of the fuel injection control accuracy accompanying the exhaust gas recirculation, there is one disclosed in Japanese Patent Laid-Open No. 4-311643.
[0003]
In this system, the partial pressure of air (fresh air) in the intake pipe and the partial pressure of the recirculated exhaust gas are obtained, respectively, so that the amount of air flowing into each cylinder can be obtained accurately. However, it is the structure which avoids getting worse by exhaust gas recirculation | reflux.
[0004]
[Problems to be solved by the invention]
However, since the conventional control method determines the amount of fuel considering the oxygen concentration in the recirculated exhaust gas as 0%, the air-fuel ratio of the engine intake mixture is leaner than the stoichiometric air-fuel ratio. The problem is that the air-fuel ratio cannot be accurately controlled to the target air-fuel ratio when oxygen is contained in the exhaust gas and the oxygen contained in the recirculated exhaust gas is added to the oxygen in the air sucked as fresh air. was there.
[0005]
In addition, the fact that the amount of fuel commensurate with the amount of oxygen actually sucked into the cylinder cannot be injected as described above leads to the fact that the ignition timing cannot be optimally set, and the ignition timing is optimal. There was also a risk of knocking out of time.
Here, in order to detect the amount of oxygen flowing into the cylinder including the amount of oxygen added by exhaust gas recirculation, an oxygen sensor for detecting the oxygen concentration is provided in the intake pipe. This is disclosed in Japanese Patent No. 247839.
[0006]
However, in the configuration in which the oxygen sensor is provided in the intake pipe as described above, since heating by the gas to be detected (exhaust) cannot be expected as in the case of providing in the exhaust pipe, means for heating from normal temperature to the activation temperature of the sensor In addition, there is a problem that the provision of such a heating means induces combustion of the air-fuel mixture in the intake pipe, and this combustion may cause a failure of the intake pipe mounting component.
[0007]
The present invention has been made in view of the above-described problems, and can prevent the control accuracy of the air-fuel ratio and the ignition timing from deteriorating due to exhaust gas recirculation without causing problems such as combustion of the air-fuel mixture in the intake pipe. The purpose is to provide.
[0008]
[Means for Solving the Problems]
Therefore, the control apparatus for an internal combustion engine according to the first aspect of the present invention is configured as shown in FIG. 1 in an internal combustion engine including an exhaust gas recirculation device that recirculates engine exhaust gas to an intake system of the engine through an exhaust gas recirculation passage. .
In FIG. 1, the recirculation oxygen amount detection means detects the amount of oxygen in exhaust gas recirculated by the exhaust gas recirculation device.
[0009]
Further, the fresh air amount detecting means detects the amount of fresh air taken into the engine.
The engine control means determines an engine control amount based on the amount of fresh air detected by the fresh air amount detection means and the amount of oxygen in the recirculated exhaust gas detected by the recirculation oxygen amount detection means.
In the control device according to the second aspect of the present invention, as shown in FIG. 1, the recirculation oxygen amount detection means includes exhaust oxygen concentration detection means for detecting the oxygen concentration in the exhaust gas recirculated by the exhaust recirculation apparatus. A recirculation exhaust amount detection means for detecting the exhaust amount recirculated by the exhaust recirculation device; an oxygen concentration in the exhaust gas detected by the exhaust oxygen concentration detection means; and a recirculation exhaust gas detected by the recirculation exhaust amount detection means. And a recirculation oxygen amount calculating means for calculating the oxygen amount in the exhaust gas recirculated by the exhaust gas recirculation device based on the amount.
[0010]
In the control device according to a third aspect of the invention, the recirculation exhaust amount detection means calculates the exhaust recirculation amount based on the effective opening area of the exhaust recirculation passage that is variably controlled and the engine operating conditions.
In the control device according to the invention of claim 4, the engine control means determines at least one of the fuel supply amount and the ignition timing as the engine control amount based on the amount of fresh air and the amount of oxygen in the recirculated exhaust gas. The configuration is determined as follows.
In the control device according to the fifth aspect of the invention, the engine control means adds the fuel amount calculated based on the oxygen amount in the recirculated exhaust to the fuel amount calculated based on the amount of the fresh air. The fuel supply amount is determined.
[0011]
[Action]
According to the control device of the first aspect of the invention, the amount of oxygen in the exhaust gas recirculated by the exhaust gas recirculation device is detected, and based on the amount of oxygen and the amount of fresh air (the amount of oxygen sucked as fresh air). The engine control amount is determined.
That is, since oxygen may be included in the exhaust gas recirculation, in that case, the oxygen in the recirculated exhaust gas is added to the oxygen sucked as fresh air and flows into the cylinder. By detecting the amount of oxygen contained in the engine, the amount of oxygen that will actually flow into the cylinder, including fluctuations due to exhaust gas recirculation, is determined, and the engine is controlled according to the amount of oxygen. .
[0012]
In the control device according to the second aspect of the invention, the oxygen amount in the exhaust gas recirculated by the exhaust gas recirculation device is calculated based on the oxygen concentration in the exhaust gas and the recirculated exhaust gas amount.
In the control device according to the invention of claim 3, since the recirculation exhaust amount varies depending on the effective opening area of the exhaust recirculation passage and the intake negative pressure of the engine, the engine operating condition correlates with the effective opening area and the intake negative pressure. Based on the above, the calculation is estimated.
[0013]
In the control device according to the invention of claim 4, as described above, the amount of oxygen actually flowing into the cylinder is obtained based on the oxygen flowing into the cylinder by exhaust gas recirculation and the amount of oxygen flowing into the cylinder as fresh air. The control accuracy of the air-fuel ratio and the ignition timing is improved by determining the fuel supply amount and the ignition timing according to the oxygen amount.
In the control device according to the fifth aspect of the invention, the control accuracy of the air-fuel ratio is improved by adding the fuel amount corresponding to the amount of oxygen flowing into the cylinder by the exhaust gas recirculation to the fuel amount corresponding to the amount of fresh air. .
[0014]
【Example】
Examples of the present invention will be described below.
FIG. 2 is a diagram illustrating a system configuration of the embodiment.
In FIG. 2, the air (fresh air) whose flow rate is adjusted by the throttle valve 2 is drawn into the internal combustion engine 1 through the intake duct 3, the throttle chamber 4, and the intake manifold 5. Here, a fuel injection valve 6 is provided in the intake port portion for each cylinder, and the fuel injected from the fuel injection valve 6 and the intake air are mixed to form an air-fuel mixture having a predetermined air-fuel ratio, The air-fuel mixture flows into each cylinder via the intake valve 7.
[0015]
The air-fuel mixture flowing into the cylinder is ignited and burned by spark ignition by the spark plug 8, and the combustion exhaust is discharged into the atmosphere via the exhaust manifold 9 and an exhaust purification device (not shown).
Further, the internal combustion engine 1 of the present embodiment is provided with an exhaust gas recirculation (EGR) device as a device for suppressing the NOx emission amount of the engine. The exhaust gas recirculation device includes an exhaust gas recirculation passage 10 that connects an exhaust passage manifold 9 (exhaust system) and an intake passage (intake system) downstream of the throttle valve 2, and exhaust gas that is interposed in the middle of the exhaust gas recirculation passage 10. The recirculation control valve 11 and a step motor 12 that opens and closes the exhaust recirculation control valve 11 are configured.
[0016]
In the above configuration, the rotation of the step motor 12 is converted into a linear motion by the worm gear, the mushroom type exhaust gas recirculation control valve 11 is moved in the axial direction, and the effective opening area of the exhaust gas recirculation passage 10 is changed. It has become.
With this configuration, when the exhaust gas recirculation control valve 11 is controlled to open, the exhaust gas is recirculated to the downstream side of the throttle valve 2 due to the pressure difference between the exhaust gas passage and the intake air passage. NOx is reduced by lowering the combustion rate and the maximum temperature of NOx.
[0017]
In this embodiment, an orifice 13 is provided in the exhaust gas recirculation passage 10 upstream of the exhaust gas recirculation control valve 11.
A control unit 15 incorporating a microcomputer inputs detection signals from various sensors, and based on these detection signals, the fuel injection amount by the fuel injection valve 6, the ignition timing by the spark plug 8, and the exhaust gas recirculation control valve 11. The opening degree (exhaust gas recirculation rate) and the like are controlled.
[0018]
The various sensors include an air flow meter 17 such as a hot-wire flow meter that detects the intake air amount (fresh air amount) of the engine as a mass flow rate, a throttle sensor 18 that detects the opening of the throttle valve 2, and the cooling water temperature of the engine. A water temperature sensor 19 that detects the crank angle, a crank angle sensor 20 that detects the crank angle, an oxygen sensor 21 (exhaust oxygen concentration detection means) that detects the oxygen concentration in the exhaust gas over a wide area, and the like are provided.
[0019]
By the way, it is desired that the fuel injection amount by the fuel injection valve 6 is set so that a mixture of the target air-fuel ratio can be obtained based on the amount of oxygen flowing into the cylinder. Also in the setting of the above, it is desired to correspond to the oxygen amount. Here, even if exhaust gas recirculation is performed, if oxygen is not included in the exhaust gas being recirculated, the fresh air amount detected by the air flow meter 17 as the fresh air amount detection means is stored in the cylinder. Appropriate injection amount control and ignition timing control are possible because it corresponds to the amount of oxygen flowing in, but if the air-fuel ratio is leaner than the stoichiometric air-fuel ratio and oxygen is contained in the recirculated exhaust gas, it will be new. The oxygen in the recirculated exhaust gas is added to the oxygen flowing in as the air, and the injection amount and ignition timing control based on the air flow meter 17 cannot cope with the added oxygen amount. The time will deviate from the aptitude value.
[0020]
Therefore, in this embodiment, the injection amount control and the ignition control corresponding to the amount of oxygen contained in the recirculated exhaust gas are executed as shown in the flowchart of FIG. In the present embodiment, the functions of the recirculation oxygen amount detection means, the recirculation exhaust amount detection means, the recirculation oxygen amount calculation means, and the engine control means are performed by the control unit 15 in software as shown in the flowchart of FIG. I have.
[0021]
In the flowchart of FIG. 3, first, at P1, the intake air amount (fresh air amount) Qa detected by the air flow meter 17 is read.
In P2, the engine speed N is calculated based on the detection signal of the crank angle sensor 20.
In P3, the basic fuel injection amount Tp (basic injection pulse width) is determined based on a constant K set based on the intake air amount Qa, the engine speed N, the flow rate characteristic of the fuel injection valve 6 and the target air-fuel ratio. Calculate (Tp = K × Qa / N).
[0022]
In P4, the coolant temperature Tw detected by the water temperature sensor 19 is read.
In P5, an increase correction coefficient KTw for increasing the basic fuel injection amount Tp is calculated based on the coolant temperature Tw.
At P6, the basic step number So of the step motor 12 is calculated to control the exhaust gas recirculation rate based on the engine speed N and the basic fuel injection amount Tp representing the engine load. As shown in FIG. 4, the step number So includes a map in which the step number So is stored in advance for each operation region divided into a plurality by the engine speed N and the basic fuel injection amount Tp. What is necessary is just to set it as the structure determined with reference. In this embodiment, the larger the step number So, the larger the opening degree of the exhaust gas recirculation control valve 11 and the larger the recirculated exhaust gas amount.
[0023]
In P7, the recirculation exhaust amount Go obtained when the step motor 12 is controlled according to the basic step number So obtained in P6 is obtained. As shown in FIG. 5, the recirculation exhaust amount Go can be obtained by storing the recirculation exhaust amount Go in advance for each operation region in which the step number So is stored and referring to the map.
[0024]
In P8, a water temperature correction coefficient STw for correcting the basic step number So is obtained based on the cooling water temperature Tw. The water temperature correction coefficient STw is set with characteristics as shown in FIG. 6, for example.
In P9, the water temperature correction coefficient STw is multiplied by the step number So obtained in P6, and the multiplication correction value is set to the final step number S.
[0025]
In P10, the recirculation exhaust amount Go obtained in P7 is multiplied by the water temperature correction coefficient STw to obtain the recirculation exhaust amount G obtained when the step motor 12 is controlled with the number of steps S.
In P11, the oxygen concentration Op in the exhaust gas is calculated based on the output of the oxygen sensor 21. In P12, the basic fuel injection amount Tp1 corresponding to the oxygen amount flowing into the cylinder by exhaust gas recirculation is calculated based on the constant K, the engine speed N, the recirculated exhaust gas amount G, and the oxygen concentration G in the exhaust gas (Tp1 = K × (G × Op / 20) / N).
[0026]
In P13, the final fuel injection amount Tp determined in P3, that is, the injection amount corresponding to fresh air, and the basic fuel injection amount Tp1 corresponding to the oxygen amount in the recirculated exhaust gas determined in P12 are finally determined. A fuel injection amount (fuel supply amount) Ti is calculated as Ti = (Tp + Tp1) × (1 + KTw) + Ts.
Note that Ts is a correction amount corresponding to a change in the invalid injection time due to the battery voltage of the fuel injection valve 6.
[0027]
The control unit 15 controls the fuel injection by the fuel injection valve 6 by outputting an injection pulse signal having a pulse width corresponding to the fuel injection amount Ti to the fuel injection valve 6 at a predetermined injection timing.
The fuel injection amount Ti calculated as described above is a value set corresponding to the sum of the amount of oxygen flowing into the cylinder as fresh air and the amount of oxygen contained in the recirculated exhaust and flowing into the cylinder. Even when oxygen is included in the recirculated exhaust gas, the injection amount corresponding to the amount of oxygen flowing into the cylinder is calculated, and the target air-fuel ratio can be obtained with high accuracy.
[0028]
In P14, an addition value TA of the basic fuel injection amount Tp corresponding to the fresh air determined in P3 and the basic fuel injection amount Tp1 corresponding to the oxygen amount in the recirculated exhaust gas determined in P12 is obtained.
In P15, the ignition timing (ignition advance value) ADV is obtained based on the injection amount TA and the engine speed N corresponding to the inflowing oxygen amount of the cylinder. The ignition timing ADV is stored in advance in a map (see FIG. 7) for each operation region divided into a plurality by the injection amount TA and the engine speed N, and is obtained by referring to the map.
[0029]
Based on the crank angle position detected by the crank angle sensor 20, an ignition signal is output to a power transistor (not shown) so as to perform ignition at the ignition timing ADV, and the ignition timing by the spark plug 8 is controlled.
If the ignition timing ADV is set as described above, the ignition timing ADV is set corresponding to the sum of the amount of oxygen flowing into the cylinder as fresh air and the amount of oxygen flowing into the cylinder by exhaust gas recirculation. It will be.
[0030]
For example, when the exhaust gas recirculation amount is changed stepwise as shown in FIG. 8, in the configuration in which the ignition timing ADV is set using only the basic fuel injection amount Tp corresponding to the fresh air, the ignition timing ADV relative to the basic fuel injection amount Tp is In this embodiment, the ignition timing ADV is set in anticipation of the amount of oxygen contained in the recirculated exhaust gas, so when oxygen is contained in the recirculated exhaust gas, it is constant regardless of ON / OFF of the exhaust gas recirculation. Even with the same fresh air amount, the ignition timing is retarded in accordance with the amount of oxygen flowing into the cylinder along with the recirculated exhaust gas, and the ignition timing is improperly advanced to control knocking. It can be avoided.
[0031]
Similarly, since the fuel injection corresponding to the amount of oxygen flowing into the cylinder together with the recirculated exhaust is performed by executing the exhaust gas recirculation, the air-fuel ratio is made leaner than the target as the exhaust gas recirculation is performed. Can be avoided.
Here, the injection amount is set corresponding to the oxygen amount contained in the reflux exhaust as described above, and the oxygen concentration detected by the oxygen sensor 21 in parallel is set as the target as shown in the flowchart of FIG. If the injection amount is feedback controlled so as to approach a value corresponding to the air-fuel ratio, the air-fuel ratio control accuracy can be further improved.
[0032]
In the flowchart of FIG. 9, each step from P21 to P32 has exactly the same processing contents as P1 to P12 in the flowchart of FIG.
In P33, the oxygen concentration Op in the exhaust gas determined in P31 is compared with the target oxygen concentration corresponding to the target air-fuel ratio.
[0033]
When the actual oxygen concentration Op is larger than the target oxygen concentration (the air-fuel ratio is leaner than the target), the routine proceeds to P34, where the air-fuel ratio feedback correction coefficient α _n is increased and changed by a predetermined value Δα to increase the injection amount. When the actual oxygen concentration Op is smaller than the target oxygen concentration (the air-fuel ratio is richer than the target), the routine proceeds to P35, where the air-fuel ratio feedback correction coefficient α _n is decreased and changed by a predetermined value Δα. Reduce.
[0034]
In P36, the basic fuel injection amount Tp corresponding to the fresh air determined in P23, the basic fuel injection amount Tp1 corresponding to the oxygen amount in the recirculated exhaust gas determined in P32, the increase correction coefficient KTw corresponding to the water temperature Tw, Based on the voltage correction amount Ts and the air-fuel ratio feedback correction coefficient α _n , the final fuel injection amount Ti is calculated as follows.
Ti = (Tp + Tp1) × (1 + KTw) × α _n + Ts
As described above, if feed-forward control is performed on the injection amount corresponding to the oxygen amount added along with the exhaust gas recirculation, and the injection amount is feedback controlled so as to obtain the target oxygen concentration, the exhaust recirculation is executed. The occurrence of the air-fuel ratio shift can be avoided with high accuracy.
[0035]
In P37 and P38, similarly to P14 and P15 in the flowchart of FIG. 3, the ignition timing ADV corresponding to the total amount of oxygen flowing into the cylinder is set.
Here, a more preferred embodiment of the exhaust gas recirculation rate control will be described with reference to the flowchart of FIG.
In the flowchart of FIG. 10, in P41, the intake air amount (mass flow rate) Qa detected by the air flow meter 17 is read.
[0036]
In P42, the engine speed N is calculated based on the detection signal of the crank angle sensor 20.
In P43, the basic fuel injection amount Tp is calculated based on the intake air amount Qa and the engine speed N.
In P44, the throttle valve opening θ detected by the throttle sensor 18 is read.
[0037]
In P45, the volume flow rate V of the intake air is obtained based on the engine speed N and the throttle valve opening θ (see FIG. 11).
In P46, the air density σ is calculated based on the mass flow rate Qa and the volume flow rate V.
In P47, the basic step number So of the step motor 12 is calculated based on the engine speed N and the basic fuel injection amount Tp (see FIG. 12).
[0038]
In P48, an air density correction coefficient Kσ for correcting the step number So according to the air density σ at that time is calculated (see FIG. 13). In the example shown in FIG. 13, the air density correction coefficient Kσ is such that when the air density decreases, the exhaust gas recirculation rate becomes smaller, and the drivability is prevented from deteriorating due to excessive exhaust gas recirculation.
In P49, the coolant temperature Tw detected by the water temperature sensor 19 is read.
[0039]
In P50, a water temperature correction coefficient Kw for correcting the exhaust gas recirculation amount is calculated based on the cooling water temperature Tw (see FIG. 14). In the example shown in FIG. 14, when the coolant temperature Tw is high and there is a tendency to overheat, the correction coefficient Kw is set larger to increase the exhaust gas recirculation rate.
In P51, the final step number S (= So × Kσ × Kw) is set by correcting the basic step number So obtained in P47 with the air density correction coefficient Kσ and the water temperature correction coefficient Kw.
[0040]
In P52, the step motor 12 is driven and controlled based on the number of steps S, so that the exhaust gas recirculation rate is appropriately controlled according to the change in the air density.
Even in the configuration in which the exhaust gas recirculation rate is set in response to the change in air density as described above, the recirculated exhaust gas amount is determined from the finally set step number S as in the embodiment shown in the flowchart of FIG. From this and the oxygen concentration in the exhaust gas, the amount of oxygen flowing into the cylinder by exhaust gas recirculation is obtained and added to the fresh air, so that the control accuracy of the air-fuel ratio and ignition timing in the state where exhaust gas recirculation is performed is increased. Can keep.
[0041]
In the above embodiment, the exhaust gas recirculation control valve 11 is opened and closed by the step motor 12. However, the structure for adjusting the exhaust gas recirculation amount is not limited to the one shown in the above embodiment, and the exhaust gas recirculation control is not limited. It is obvious that a configuration using a linear solenoid valve as the valve 11 may be used.
[0042]
【The invention's effect】
As described above, according to the control apparatus for an internal combustion engine according to the first aspect of the present invention, the amount of oxygen contained in the recirculated exhaust gas is detected, so that the fluctuation amount due to the exhaust gas recirculation is actually introduced into the cylinder. Since the engine is controlled in accordance with the amount of oxygen, the accuracy of the engine control performed in accordance with the amount of intake oxygen is improved.
[0043]
According to the control apparatus for an internal combustion engine of the second aspect of the invention, there is an effect that the amount of oxygen in the recirculated exhaust gas can be accurately detected based on the oxygen concentration in the exhaust gas and the recirculated exhaust amount.
According to the control apparatus for an internal combustion engine according to the invention of claim 3, the effect that the recirculation exhaust amount can be accurately estimated based on the effective opening area of the exhaust recirculation passage and the engine operating condition (engine intake negative pressure). There is.
[0044]
According to the control apparatus for an internal combustion engine of the fourth aspect of the present invention, the control accuracy in consideration of the oxygen amount in the recirculated exhaust gas is set to the fuel supply amount and the ignition timing, thereby improving the control accuracy of the air-fuel ratio and the ignition timing. There is an effect that an air-fuel ratio shift or knocking can be avoided as the exhaust gas recirculates.
According to the control apparatus for an internal combustion engine of the fifth aspect of the invention, even when oxygen is contained in the recirculated exhaust gas, the fuel supply amount corresponding to the oxygen amount flowing into the cylinder is calculated, and There is an effect that the fuel ratio can be controlled with high accuracy.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a basic 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 fuel injection and ignition control of the first embodiment.
FIG. 4 is a graph showing a characteristic of an exhaust gas recirculation rate in an example.
FIG. 5 is a graph showing the characteristics of the exhaust gas recirculation amount in the embodiment.
FIG. 6 is a diagram showing a characteristic of temperature correction of the exhaust gas recirculation rate.
FIG. 7 is a graph showing the characteristics of basic ignition timing in the embodiment.
FIG. 8 is a time chart for explaining the effect of the embodiment.
FIG. 9 is a flowchart showing fuel injection and ignition control of the second embodiment.
FIG. 10 is a flowchart showing another embodiment of exhaust gas recirculation rate control.
FIG. 11 is a diagram showing detection characteristics of volume flow rate in an example.
FIG. 12 is a graph showing a characteristic of an exhaust gas recirculation rate in an example.
FIG. 13 is a diagram showing the state of air density correction of the exhaust gas recirculation rate in the example.
FIG. 14 is a diagram showing a state of water temperature correction of the exhaust gas recirculation rate in the example.
[Explanation of symbols]
1 Internal combustion engine 2 Throttle valve 6 Fuel injection valve 8 Spark plug
10 Exhaust gas recirculation passage
11 Exhaust gas recirculation control valve
12 step motor
15 Control unit
17 Air flow meter
18 Throttle sensor
19 Water temperature sensor
20 Crank angle sensor
21 Oxygen sensor

Claims (5)

In an internal combustion engine provided with an exhaust gas recirculation device that recirculates engine exhaust gas to an intake system of the engine via an exhaust gas recirculation passage,
Recirculation oxygen amount detection means for detecting the amount of oxygen in the exhaust gas recirculated by the exhaust gas recirculation device;
Fresh air amount detection means for detecting the amount of fresh air sucked into the engine;
Engine control means for determining a control amount of the engine based on the amount of fresh air detected by the fresh air amount detection means and the amount of oxygen in the recirculated exhaust gas detected by the recirculation oxygen amount detection means;
A control device for an internal combustion engine, comprising: The reflux oxygen amount detection means comprises
Exhaust oxygen concentration detection means for detecting the oxygen concentration in the exhaust gas recirculated by the exhaust gas recirculation device;
Recirculation exhaust amount detection means for detecting the exhaust amount recirculated by the exhaust recirculation device;
The amount of oxygen in the exhaust gas recirculated by the exhaust gas recirculation device is calculated based on the oxygen concentration in the exhaust gas detected by the exhaust oxygen concentration detecting means and the amount of the recirculated exhaust gas detected by the recirculated exhaust gas amount detecting means. Reflux oxygen amount calculating means;
The control apparatus for an internal combustion engine according to claim 1, comprising: 3. The control apparatus for an internal combustion engine according to claim 2, wherein the recirculation exhaust amount detection means calculates an exhaust recirculation amount based on an effective opening area of the exhaust recirculation passage that is variably controlled and an engine operating condition. The engine control means determines at least one of a fuel supply amount and an ignition timing as an engine control amount based on the amount of fresh air and the amount of oxygen in the recirculated exhaust gas. A control apparatus for an internal combustion engine according to any one of claims 1, 2 and 3. The engine control means adds the recirculated exhaust gas to a fuel amount calculated based on the fresh air amount. 4. The control apparatus for an internal combustion engine according to claim 1, wherein the fuel supply amount of the engine is determined by adding the fuel amount calculated based on the oxygen amount in the engine.

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