JP2005171765A - Control device and control method of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve setting accuracy of the ignition timing, by accurately determining an opening correction value corresponding to a deviation and an error of an exhaust air recirculating flow rate by a change in an environmental factor and the deterioration with the lapse of time. <P>SOLUTION: This control device has an exhaust air recirculating device for controlling the exhaust air recirculating flow rate by adjusting opening of an exhaust air recirculation control valve 26 arranged in an exhaust air recirculating passage 25. The exhaust air recirculation control valve 26 is temporarily operated for opening in idle speed feedback control for controlling an engine speed toward a target value by making a feedback process. The opening correction value of the exhaust air recirculation control valve 26 is calculated on the basis of a control parameter changing by this opening operation. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to control of an internal combustion engine equipped with an exhaust gas recirculation (EGR) device.

In Patent Document 1, an exhaust gas recirculation control valve is provided in an exhaust gas recirculation passage from the exhaust passage to the intake air passage in order to improve fuel efficiency and exhaust performance of an internal combustion engine (engine) for a vehicle, and its opening degree is controlled. Thus, an exhaust gas recirculation device that adjusts the exhaust gas recirculation amount and rate is disclosed. In a system including such an exhaust gas recirculation device, it is desirable to adjust the ignition timing according to the exhaust gas recirculation amount. Basically, as the exhaust gas recirculation amount increases, the combustion in the combustion chamber becomes slower, so the ignition timing may be adjusted to the advance side.
JP 2001-82260 A

  However, since it is difficult to accurately measure the exhaust gas recirculation amount, the deviation / error between the control target value of the exhaust gas recirculation amount and the actual value increases due to changes in environmental factors, component variations, deterioration over time, etc. As a result, the setting accuracy of the ignition timing is lowered, and there is a possibility that fuel efficiency and driving performance are lowered.

  The above-mentioned Patent Document 1 is provided with an intake pressure sensor for detecting the intake pressure in the intake passage, and the target value and actual value of the exhaust gas recirculation amount based on the change of the intake pressure that changes due to the opening / closing operation of the exhaust gas recirculation control valve. The technique which calculates | requires the deviation and error is disclosed. However, the technique of Patent Document 1 requires components such as an intake pressure sensor, which increases costs and weight.

  The present invention has been made in view of such a problem, and the exhaust gas recirculation control valve corresponding to the deviation between the target value and the actual value of the exhaust gas recirculation amount without substantially increasing the number of parts. An object of the present invention is to provide a novel control device for an internal combustion engine that can satisfactorily obtain an opening correction value.

  An exhaust gas recirculation device that controls the exhaust gas recirculation amount by adjusting the opening degree of an exhaust gas recirculation control valve provided in the exhaust gas recirculation passage that recirculates exhaust gas from the exhaust gas passage to the intake air passage; and a detected value and a target value of the engine speed Idle speed control means for performing idle speed feedback control for feedback control of the engine speed toward the target value by adjusting the amount of intake air based on the deviation of the engine speed. During the idling engine speed feedback control, the exhaust gas recirculation control valve is temporarily opened, and the opening correction value of the exhaust gas recirculation control valve is calculated based on a control parameter that changes due to the opening operation.

  According to the present invention, the opening correction value of the exhaust gas recirculation control valve corresponding to the deviation between the target value of the exhaust gas recirculation amount and the actual value is obtained satisfactorily without using components such as the intake pressure sensor described above. As a result, the ignition timing setting accuracy can be improved. In addition, since the opening correction value is calculated during idle speed feedback control in a steady state, that is, in a state where there is substantially no change in the rotation speed or load accompanying the accelerator operation, the opening correction value is accurately calculated. Can be calculated.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. FIG. 8 is a block diagram schematically showing a spark ignition gasoline engine to which a control device according to an embodiment of the present invention is applied.

  The air adjusted by the electronically controlled throttle 23 is stored in the intake collector 2 and then introduced into the combustion chamber 5 of each cylinder through the intake manifold 3. Fuel is intermittently injected and supplied into the intake port 4 from a fuel injection valve 21 disposed in the intake port 4 of each cylinder. The fuel injection amount and the injection timing are determined based on the intake air amount detected by the air flow meter 32 and the engine speed (speed) calculated based on the signals from the crank angle sensors (33, 34). 31.

  The fuel injected toward the intake valve 15 is mixed with intake air to form an air-fuel mixture. The air-fuel mixture is confined in the combustion chamber 5 by closing the intake valve 15 and compressed by the rise of the piston 6, and the spark plug 14 is ignited and burned. The gas pressure due to the combustion works to push down the piston 6, and the reciprocating motion of the piston 6 is converted into the rotational motion of the crankshaft 7. The exhaust gas after combustion is discharged into the exhaust passage 8 when the exhaust valve 16 is opened.

  A three-way catalyst 9 is provided in the exhaust passage 8 as an exhaust purification catalyst. As is well known, the air-fuel ratio of the exhaust is centered on the stoichiometric air-fuel ratio by performing feedback control of the air-fuel ratio of the exhaust based on a signal from an oxygen sensor (not shown) provided upstream of the three-way catalyst 9. HC, CO and NOx contained in the exhaust can be simultaneously and efficiently removed by the three-way catalyst 9 while being maintained in a narrow range.

  The electric control throttle 23 is driven by a throttle motor 24. Since the torque required by the driver appears in the amount of depression of the accelerator pedal 41 (accelerator opening), the engine controller 31 determines a target torque based on a signal from the accelerator sensor 42, and a target for realizing this target torque. An intake air amount is determined, and a command signal is output to the throttle motor 24 so that the target intake air amount is obtained, and the opening degree of the electric throttle 23 is controlled.

  An exhaust gas recirculation (EGR) device that recirculates exhaust gas in the exhaust passage 8 to the intake passage 3 is provided mainly to improve fuel consumption and exhaust performance. This EGR device is provided in the exhaust gas recirculation passage 25 that recirculates exhaust gas from the intake passage 3 to the exhaust gas passage 8, and the exhaust gas that adjusts the exhaust gas recirculation (EGR) amount and rate according to the opening degree. A reflux control valve, that is, an EGR valve 26, and a step motor 27 as an electric actuator that drives the EGR valve 26 are provided. As is well known, when the step motor 27 receives the target number of steps from the engine controller 31, the step motor 27 rotates by the number of steps to move the valve body of the EGR valve 26 up and down in the axial direction, thereby increasing the opening degree of the EGR valve 26. adjust. Generally, when the number of steps increases, the opening degree of the EGR valve 26 increases in proportion to the number of steps, and the EGR amount increases. The engine controller 31 controls the opening degree of the EGR valve 26 according to the engine operating conditions, and adjusts the EGR amount / rate. In consideration of engine stability, normally, in an idle operation region as described later, the opening of the EGR valve 26 is set to zero and the application of EGR gas is prohibited.

  Also, a VTC (valve timing control) mechanism 28 capable of continuously changing the valve timing of the intake valve 15 is provided in order to achieve both improvement in output / torque and improvement in fuel consumption / exhaust performance. .

  In the idling range, the engine speed detection value calculated based on the crank angle sensor (33, 34) and the control target value, ie, the idling target speed so as to maintain the engine speed at a predetermined target value. Based on the deviation, the opening degree of the electric throttle 23 is controlled, and the so-called idle speed feedback control for controlling the fuel injection amount is performed (idle speed control means). The idle target rotation speed is set based on the EGR amount and the like in addition to the auxiliary machine load and the cooling water temperature.

  The target value of the ignition timing is basically set based on engine operating conditions such as engine speed, water temperature, accelerator opening, throttle opening, and EGR flow rate. When the occurrence frequency / degree of knocking detected by the knock sensor 29 exceeds a predetermined value, the ignition timing is retarded or retarded within a predetermined knock control region. That is, ignition timing feedback control (trace knock control) is performed based on the detection signal of the knock sensor 29 (ignition timing feedback control means).

  As is well known, the feedback control described above is proportional-integral (PI) control using proportional (P) and integral (I) components. These controls are stored and executed by the engine controller 31 described above.

  As a feature of the present embodiment, when a predetermined operating condition (FIG. 2) including that during idling speed feedback control is established, the EGR valve 26 is temporarily opened, and the control parameter changed by this opening operation is set. Based on this, the learning value EGSTPGK of the valve opening area corresponding to the opening correction value of the EGR valve 26 is calculated (opening correction value calculating means). This learned value is reflected in the setting of the ignition timing.

  FIG. 1 is a flowchart showing a flow of learning control for calculating the valve opening area learning value EGSTPGK. This routine is repeatedly executed by the engine controller 31 every predetermined period. FIG. 4 is a time chart during this learning control.

  In step (abbreviated as S in the figure) 1, it is determined whether or not the operating condition for performing the learning control is satisfied by the subroutine shown in FIG. Specifically, as shown in FIG. 2, the determination process of Steps 13 to 17 corresponding to various operating conditions for which learning control is to be performed is performed, and the process proceeds to Step 18 a only when the determinations of Steps 13 to 17 are all affirmed. Then, the learning permission determination flag EGRKKOK is set to 1 to allow learning control. If any of Steps 13 to 17 is denied, the process proceeds to Step 18b, where the learning permission determination flag EGRKOK is reset to 0. The execution of learning control is prohibited.

  In step 13, it is determined whether the maximum value BETAMAX of the ignition timing feedback amount BETA of the ignition timing feedback control based on the detection signal of the knock sensor described above is larger than a predetermined value EGGKBETA. This EGGKBETA is set as a value corresponding to the maximum value of the ignition timing feedback amount when the EGR is OFF (the opening degree of the EGR valve is 0), and corresponds to an environmental factor / component variation excluding the EGR device. Therefore, when the maximum value BETAMAX of the ignition timing feedback amount including when the EGR is ON (when the EGR valve is opened) exceeds the above-mentioned EGGKBETA, it is determined that the EGR flow rate has decreased, and the learning control is permitted. In other words, when the maximum value BETAMAX of the ignition timing feedback amount is less than or equal to the predetermined value EGGKBBETA, the execution of learning control is prohibited, so that the learning frequency is minimized and the decrease in idle driving performance due to learning control is minimized. ing.

  In step 14, it is determined whether the idle speed feedback control (ISC) is being executed. In steps 15 to 17, it is determined whether or not the operation state is such that learning control can be performed stably. That is, in step 15, it is determined whether the engine water temperature TWN is higher than the predetermined value EGGKTW, that is, whether the engine temperature is in the water temperature range where the torque fluctuation is stable. In step 16, it is determined whether the neutral switch NEUTSW is 0, that is, OFF. In other words, in the neutral state such as the N range or the P range, the idle stability is relatively low as compared with the state where the engine such as the D range and the axle are connected. Ban. In step 17, it is determined whether or not the load of the auxiliary equipment is within a predetermined range in order to avoid a decrease in the learning value calculation control due to fluctuations in the load of the auxiliary equipment such as the air conditioner compressor, the alternator and the power steering. To do.

  Referring to FIG. 1 again, in step 2, it is determined whether or not the permission flag EGRGKOK in step 1 is 1, that is, whether or not the learning is permitted. If the permission flag EGRGKOK is 1, the process proceeds to step 3, and if the permission flag EGRGKOK is not 1, the routine is terminated without performing learning control.

  In step 3, the learning target idle speed NEEGOK is set as the idle target speed. As shown in FIG. 4, the learning target idle speed NEEGOK is set to be, for example, about 600 rpm higher than the normal idle target speed NEOK so as to avoid a decrease in idle driving performance during learning. .

  In step 4, it is determined whether the deviation between the engine speed measurement value LNRPM calculated based on the detection values of the crank angle sensors 43 and 44 and the learning target value NEEGOK is less than a predetermined value N1 (for example, 50 rpm). . That is, the learning control is started until the measured value LNRPM of the engine speed is sufficiently close to the learning target value NEEGOK so that the learning control is performed after the engine speed is stabilized (specifically, the temporary control of the EGR valve). Forbidden / standby). T1 in FIG. 4 corresponds to the timing at which the determination in step 4 is switched to affirmative and the process proceeds to step 5.

  In step 5, a step deviation amount EGSTPDEF corresponding to the deviation of the EGR valve step number is calculated by the subroutine of FIG. This EGSTPDEF is a deviation between the control target value of the step number of the step motor and the actual value, and corresponds to the opening degree of the EGR valve 26 by the opening operation of the EGR valve.

  Referring to FIG. 3, in step 19, the EGR valve 26 is opened for a predetermined amount and for a predetermined period with a predetermined time schedule. Specifically, the target number of steps of the step motor 27 that drives the EGR valve 26 is held at “5” which is a predetermined value EGSTPDGK for 2 seconds. This step number “5” corresponds to an opening of the EGR valve of about 10 to 20%.

  In step 20, a change amount QFBIEGR corresponding to the integral of the idle speed feedback control is calculated as a control parameter that changes as the EGR valve opens. As shown in FIG. 4, this QFBIEGR corresponds to an increase due to the opening operation of the EGR valve with respect to the integral when the EGR is OFF. Therefore, QFBIEGR follows with a delay to the change in EGSTPM0 corresponding to the actual number of steps. For example, it is possible to separately store the I amount of the feedback amount when EGR is OFF, and obtain QFBIEGR from the deviation from this value. In step 21, the QFBIEGR maximum value QFBIEEGMX is sequentially updated and stored.

  In step 22, the actual step number EGSTPGK0 corresponding to the number of steps actually opened is calculated and estimated from the integrated maximum displacement amount QFBIEEGMX with reference to the TEGSTPGK table shown in FIG. Here, the TEGSTPGK table has a value that matches the correlation between QFBIEGMMX and EGSTPGK0 in the new state and the initial state when the EGR valve is opened with a predetermined time schedule (2 seconds, 5 steps) as described above. It is input in advance.

  In step 23, a deviation between the target step number EGSTPDKK (in this example, “5”) and the actual step number EGSTPGK0 is calculated as a step deviation amount EGSTPDEF.

  Referring again to FIG. 1, in step 6, it is determined whether the monitored value (detected value) EGSTPM0 of the number of steps of the EGR valve 26 has become 0 from a value other than 0 (zero). That is, it is determined whether the EGR valve 26 that has been temporarily opened for learning control is actually closed. T3 in FIG. 4 corresponds to the timing when the determination in step 6 is affirmed and the process proceeds to step 7.

  In step 7, the previous learning value EGSTPGK stored and stored in the memory of the engine controller 31 is rewritten and updated to the maximum value of the step deviation amount EGSTPDEF. The learning value EGSTPGK corresponds to the final deviation / error between the control target value of the EGR valve 26 and the actual value, that is, the final opening correction value of the EGR valve 26.

  In step 8, it is determined whether the I-minute variation amount QFBIEGR due to the opening operation of the EGR is 0 or less than a predetermined value QFBIEGE which is a local minimum value close to 0. That is, with respect to the switching operation of the EGR valve 26 from “open” to “closed” (see EGSTPM0, T2 to T3 in FIG. 4), the change in the intake air amount due to the feedback control is delayed due to the intake volume and the like. Therefore, the system waits until the fluctuation of the intake air amount converges based on the I part of the feedback control. 4 corresponds to the timing at which the determination in step 8 is affirmed and the process proceeds to step 9.

  In step 9, the idle target speed used for the idle speed feedback control is rewritten from the learning value NEEGOK to the normal value NEOK and updated. As a result, the normal idle speed feedback control state is restored.

  In step 10, the value of BETAMAX, which will be described later, is initialized and reset to 0 in addition to the flags EGRKKOK and QFBIEGMMX in preparation for the next learning.

  FIG. 6 shows an ignition timing setting routine reflecting the learning value EGSTPGK. In step 31, the actual step number EGSTPMF corresponding to the actual step number is calculated from the difference between the monitor value EGSTPM0 of the step number and the learning value EGSTPGK by the following equation (1).

EGSTPMF = EGSTPM0−EGRSTPGK (1)
In step 32, the actual opening area (opening) TEGARARF of the EGR valve is calculated based on the actual step number EGSTPMF with reference to the TTAEGS table showing the relationship between the opening area and the number of steps shown in FIG. In step 33, an estimated EGR rate that is an EGR rate reflecting the learning value EGRSTPGK is calculated based on the actual opening area TEGRARRF. In step 34, the ignition timing is calculated based on the estimated EGR rate. As a result, the learning value EGRSTPGK taking into account changes in environmental factors, deterioration with time, and the like is reflected in the ignition timing setting, and the ignition timing setting accuracy is improved.

  The technical ideas that can be grasped from the above embodiments are listed below together with the effects thereof.

  (1) An exhaust gas recirculation device that controls the exhaust gas recirculation amount by adjusting the opening degree of the exhaust gas recirculation control valve 26 provided in the exhaust gas recirculation passage 25 that recirculates exhaust gas from the exhaust passage 8 to the intake air passage 3, and the engine speed Idle speed control means for performing idle speed feedback control for feedback control of the engine speed toward the target value by adjusting the amount of intake air based on the deviation between the detected value of the engine and the target value, and the idle speed During the numerical feedback control, the exhaust gas recirculation control valve 26 is temporarily opened (step 19), and the opening correction value EGSTPGK of the exhaust gas recirculation control valve 26 is calculated based on the control parameter QFBIEGR that changes due to the opening operation. Opening degree correction value calculation means (steps 5 to 7).

  By reflecting the opening correction value EGSTPGK calculated in this way, for example, in the setting of the ignition timing, errors and variations in the opening degree of the exhaust gas recirculation control valve 26 due to deterioration with time, changes in environmental factors, etc. are effectively obtained. By offsetting and absorbing, the ignition timing can be set with high accuracy. Since the opening correction value EGSTPGK is calculated during idle speed feedback control in a steady state, that is, in a state where there is substantially no change in the rotation speed or load accompanying the accelerator operation, this opening correction value Can be calculated accurately.

  (2) The control parameter that changes due to the opening operation is an integral part of the idle speed feedback control. By utilizing the integral used for idle speed feedback control in this way, it is not necessary to provide a hardware configuration such as a pressure sensor, and the opening correction value can be calculated without adding parts or increasing costs. And can be easily applied to existing internal combustion engines.

  (3) The ignition timing is set based on the opening correction value EGSTPGK of the exhaust gas recirculation control valve 26 (FIG. 6). In this way, by accurately reflecting the opening correction value EGSTPGK, which is a learned value, in the ignition timing setting, the ignition timing can be set with high accuracy so as to cancel out errors and variations in the exhaust gas recirculation amount due to deterioration over time. It is possible to improve fuel efficiency and combustion stability.

  (4) a knock sensor 29 for detecting the occurrence of knocking, and ignition timing feedback control means for feedback controlling the ignition timing based on the detection signal of the knock sensor 29, and an integral amount BETA of the ignition timing feedback control When the maximum value BETAMAX is less than or equal to the predetermined value EGGKBBETA, the execution of the opening correction value calculating means is prohibited (step 13).

  As a calculation method of the opening correction value different from the above embodiment, when the exhaust gas recirculation amount varies to the larger side, the combustion deteriorates and the rotational fluctuation becomes large. Therefore, the exhaust fluctuation is detected by detecting the rotational fluctuation. It is conceivable to calculate the opening correction value of the engine and reduce the exhaust gas recirculation amount based on the opening correction value. However, with this method, when the exhaust gas recirculation amount varies to the side where the exhaust gas recirculation amount is small, the combustion shifts to a stable side, so the exhaust gas recirculation amount cannot be detected well due to rotational fluctuations, and the opening correction value is substantially reduced. It cannot be calculated. If the exhaust gas recirculation amount varies to the side where the exhaust gas recirculation amount is small, the ignition timing is set to an over-advanced angle, so that knocking is likely to occur, which may cause vibration and noise.

  In this embodiment, when the integral maximum value BETAMAX of the ignition timing feedback control exceeds a predetermined value EGGGKBET, that is, when the exhaust gas recirculation amount varies to the side where the exhaust gas recirculation amount is small, the calculation processing of the opening correction value is permitted. In other words, since the calculation of the opening correction value is prohibited when the integral maximum value BETAMAX of the ignition timing feedback control is less than or equal to the predetermined value EGGGKBETA, the calculation frequency of the opening correction value is minimized, A decrease in drivability associated with this calculation operation can be minimized.

  (5) The opening degree correction calculating means increases the target value NEEGOK for the idle speed higher than normal (NEOK) (step 3).

  During idling, since the intake pressure is high boost and the fresh air flow rate is small, variation in the exhaust gas recirculation rate tends to increase due to variation in the opening area of the exhaust gas recirculation control valve, and the combustion state tends to become unstable. Therefore, when performing the opening degree correction value calculation process described above, the idle speed target value NEEGOK is set higher than normal (NEOK) so as to avoid a decrease in combustion state and misfire.

  (6) It has a step motor 27 for driving the exhaust gas recirculation control valve, and the opening correction value calculating means operates the step motor 27 for a predetermined period with a predetermined target step number EGSTPDGK (step 19). The actual step number EGSTPGK0 corresponding to the actual step motor step number is calculated on the basis of the maximum displacement amount QFBIEEGMX corresponding to the integral of the idling speed feedback control that varies depending on the step number (step 22). Based on the step number EGSTPDGK, a step deviation amount EGSTPDEF corresponding to the opening correction value is calculated (step 23).

  By calculating the opening correction value using the integral amount of the idle speed feedback control in this way, it is not necessary to provide a hardware configuration such as a pressure sensor, which may lead to the addition of parts and an increase in cost. Therefore, it can be easily applied to existing internal combustion engines. In addition, since the opening correction value is calculated by directly using the number of steps of the step motor, which is the actual control command value, the calculation process is simplified and calculation errors are minimized. It is suppressed.

  As described above, the present invention has been described based on the specific embodiments. However, the present invention is not limited to the above-described embodiments, and includes various modifications and changes without departing from the spirit of the present invention. . For example, in the above embodiment, the calculated opening correction value is reflected in the setting of the ignition timing. However, the present invention is not limited to this. For example, it may be reflected in the setting of the exhaust gas recirculation amount / rate of the exhaust gas recirculation control valve itself.

The flowchart which shows the calculation routine of the opening area learning value EGSTPGK of the exhaust gas recirculation control valve concerning one Example of this invention. A subroutine for setting the learning value calculation permission flag EGRGKOK. Subroutine for calculating the step deviation amount EGSTPDEF. The time chart at the time of the said learning value calculation. A TEGSTPGK table for setting the actual step number EGSTPGK0. The flowchart which shows the setting routine of the ignition timing using the learning value EGSTPGK. A TTAEGS table for setting the actual opening area TEGARARF of the exhaust gas recirculation control valve. 1 is a system diagram showing a vehicle internal combustion engine to which a control device according to an embodiment of the present invention is applied.

Explanation of symbols

3 ... Intake passage 8 ... Exhaust passage 14 ... Spark plug 25 ... Exhaust gas recirculation passage 26 ... Exhaust gas recirculation control valve 27 ... Step motor 29 ... Knock sensor 31 ... Engine controller

Claims (7)

An exhaust gas recirculation device that controls an exhaust gas recirculation amount by adjusting an opening degree of an exhaust gas recirculation control valve provided in an exhaust gas recirculation passage that recirculates exhaust gas from the exhaust passage to the intake air passage;
Idle speed control means for performing idle speed feedback control for feedback control of the engine speed toward the target value by adjusting the intake air amount based on the deviation between the detected value of the engine speed and the target value;
During the idling speed feedback control, the exhaust gas recirculation control valve is temporarily opened, and the exhaust gas recirculation control valve opening amendment value is calculated based on the control parameter that is changed by the opening operation. Means,
A control apparatus for an internal combustion engine.   2. The control apparatus for an internal combustion engine according to claim 1, wherein the control parameter that changes due to the opening operation is an integral part of the idle speed feedback control.   The control apparatus for an internal combustion engine according to claim 1 or 2, wherein an ignition timing is set based on an opening correction value of the exhaust gas recirculation control valve. A knock sensor for detecting the occurrence of knocking;
Ignition timing feedback control means for feedback controlling the ignition timing based on the detection signal of the knock sensor,
4. The control device for an internal combustion engine according to claim 3, wherein execution of the opening correction value calculating means is prohibited when a maximum value of integral of the ignition timing feedback control is not more than a predetermined value.   The control device for an internal combustion engine according to any one of claims 1 to 4, wherein the opening degree correction calculation means makes the target value of the idle speed higher than usual. A step motor for driving the exhaust gas recirculation control valve;
The opening correction value calculating means operates the step motor at a predetermined target number of steps for a predetermined period, and based on the maximum displacement amount of the integral of the idle speed feedback control that changes due to this operation, 6. The actual step number corresponding to the step number is calculated, and a step deviation amount corresponding to the opening correction value is calculated based on the actual step number and the target step number. Control device for internal combustion engine. An exhaust gas recirculation device that controls the exhaust gas recirculation amount by adjusting the opening degree of an exhaust gas recirculation control valve provided in the exhaust gas recirculation passage that recirculates exhaust gas from the exhaust gas passage to the intake air passage; and a detected value and a target value of the engine speed In the control method of the internal combustion engine, the idle speed control means for performing the idle speed feedback control for performing feedback control of the engine speed toward the target value by adjusting the intake air amount based on the deviation of
During the idle speed feedback control, the exhaust gas recirculation control valve is temporarily opened, and an opening correction value of the exhaust gas recirculation control valve is calculated based on a control parameter that changes due to the opening operation. A method for controlling an internal combustion engine.

Images