JP5023879B2 - Engine control device - Google Patents

Description

  The present invention relates to an engine control device, and more specifically, a technique for realizing air-fuel ratio control with higher accuracy by enabling calculation of an air-fuel ratio feedback correction amount not only during steady operation but also during transient operation. About.

  Air-fuel ratio feedback control is already well known as a technique for improving the accuracy of air-fuel ratio control in an engine. The feedback control of the air-fuel ratio is performed by detecting the air-fuel ratio of the exhaust (hereinafter simply referred to as “air-fuel ratio”) by using an oxygen sensor or the like, and the detected air-fuel ratio with respect to the target air-fuel ratio. This is configured as a control for calculating a feedback correction amount corresponding to the magnitude of the deviation and thereby correcting the fuel supply amount to the engine.

  Some of the air-fuel ratio controls generally incorporate a feedback correction amount learning function. This is determined in such a way that the learning correction amount is calculated so as to reduce the deviation of the feedback correction amount obtained during execution of the feedback control from the reference value, and this is corresponding to each driving state. The learning correction amount is stored in the learning area, and the stored learning correction amount is read out during the subsequent operation, thereby correcting the fuel supply amount.

  However, with regard to feedback control performed by comparing the air-fuel ratio and its target value (target air-fuel ratio) in this way, the actual intake air amount changes with respect to the operation of the accelerator pedal, particularly during engine transient operation. Since a delay occurs and this delay appears in the air-fuel ratio, it is difficult to stably and appropriately control the engine by a simple comparison between the air-fuel ratio and the target air-fuel ratio. For example, during acceleration, when the accelerator pedal is depressed, the target air-fuel ratio decreases, and the fuel supply amount increases accordingly. Therefore, the supply of air into the cylinder is delayed, causing a temporary decrease (drop) in the air-fuel ratio. Here, if the deviation of the air-fuel ratio from the target air-fuel ratio is detected and the fuel supply amount is corrected by the feedback correction amount according to the detected magnitude, the feedback correction amount decreases due to the drop in the air-fuel ratio. In other words, unnecessary reduction correction is applied to the fuel supply amount, resulting in a shortage of the fuel injection amount.

In order to avoid such problems, the engine operating state is determined based on changes in the vehicle speed or accelerator operation amount, etc., feedback control is not performed during transient operation, and feedback correction amount is calculated only during steady operation. In addition, the learning correction amount is calculated and stored (updated) (Patent Document 1).
JP 2003-020980 A (paragraph number 0032)

  However, there are not so many scenes where the engine is constantly operated, and when feedback control is prohibited except during steady operation, the learning area and frequency for storing (updating) the learning correction amount are sufficient. There is a problem that it is difficult to secure. Therefore, in the transient operation, instead of not performing the feedback control, the learning correction amount obtained in the steady operation is applied to suppress the excess or deficiency in the fuel supply amount. .

Here, about what applies the learning correction amount obtained at the time of steady operation, there exist the following problems.
First, the feedback control can compensate for changes over time such as the operating characteristics of the injector, and the learning correction amount used during transient operation by application is obtained during steady operation. The problem is that it does not necessarily accurately reflect the actual operating characteristics and the like of the injector under operating conditions accompanied by a transient change at that time.

  Second, if feedback control is not performed during transient operation, the learning area in which the feedback correction amount is calculated and the learning correction amount is stored is limited. This is a problem that the correction amount must be calculated by interpolation between learning areas.

  In consideration of the above problems, the present invention sets the target air-fuel ratio in accordance with the actual change in intake air amount during transient operation such as acceleration, so that not only during steady operation but also during transient operation. It is an object of the present invention to improve the accuracy of air-fuel ratio control by making it possible to calculate a feedback correction amount without excess or deficiency.

In the present invention, the accelerator operation amount of the driver is detected, and based on this, the target air-fuel ratio of the air-fuel mixture is calculated. In addition to detecting the actual operating air-fuel ratio, the engine intake air amount or the operating state amount correlated therewith is detected as the engine operating state amount, and the calculated target air-fuel ratio is determined based on the detected operating state amount. The amount of deviation of the detected driving state quantity with respect to the target value of the driving state quantity (hereinafter simply referred to as “deviation amount”) is detected. When the change amount per unit time of the accelerator operation amount exceeds a predetermined amount, the calculated target air-fuel ratio is corrected based on the detected deviation amount, the corrected target air-fuel ratio is calculated, and the calculated correction Based on the target air-fuel ratio and the detected operating air-fuel ratio, a control command value for controlling the air-fuel ratio of the air-fuel mixture is calculated.

  According to the present invention, the engine operating state amount is detected, the deviation amount of the detected operating state amount from the target value is detected, the target air-fuel ratio is corrected based on the detected deviation amount, and the control command The corrected target air-fuel ratio used for calculating the value was calculated. Here, since the target value of the operating state quantity is in accordance with the target air-fuel ratio and in accordance with the change, the correction is based on the detected operating state quantity and the deviation amount of the target value. The obtained target air-fuel ratio (corrected target air-fuel ratio) is calculated based on a transient change in the operating state quantity under actual operating conditions. Therefore, according to the present invention, based on the corrected target air-fuel ratio thus obtained, it is possible to calculate the feedback correction amount without excess or deficiency even during transient operation, and to realize air-fuel ratio control with higher accuracy. can do.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 shows a configuration of an engine 1 according to an embodiment of the present invention.
The engine 1 according to the present embodiment is a gasoline engine and constitutes a drive source for a vehicle such as a passenger car.

  A throttle valve 12 for controlling the intake air amount of the engine 1 is installed in the intake passage 11. The throttle valve 12 is a butterfly valve and is driven by a step motor provided as a throttle actuator 121. The throttle actuator 121 operates based on a command signal from the control unit 101 described later, and drives the throttle valve 12 to an opening degree corresponding to this signal. A surge tank 13 is interposed downstream of the throttle valve 12, and the sucked air flows into the surge tank 13 at a flow rate adjusted by the throttle valve 12. It is distributed to the cylinders. The manifold portion communicates with the combustion chamber of each cylinder via a port portion of the intake passage 11 formed in the cylinder head.

  In the cylinder head, fuel supply injectors 14a to 14d are installed toward the port portions of the respective cylinders, and the injectors 14a to 14d are operated by a command signal from the control unit 101 to supply fuel into the port portions. Spray. Fuel sent out by a fuel pump (not shown) is supplied to each injector 14 a to 14 d through a fuel supply passage 15.

  The cylinder head is provided with spark plugs 21a to 21d on a substantially center line of each cylinder. The spark plugs 21a to 21d are also operated by a command signal from the control unit 101, and ignite at a predetermined timing determined by the control unit 101 to cause combustion.

  Exhaust gas after combustion is released into the atmosphere via the exhaust passage 31. In the exhaust passage 31, a catalytic converter 32 incorporating an exhaust purification catalyst is installed. Exhaust gas discharged from the engine 1 is discharged into the atmosphere after harmful components such as NOx are purified in the catalytic converter 32.

  In the control unit 101, a detection signal from the accelerator sensor 151 for detecting the amount of depression of the accelerator pedal (hereinafter referred to as “accelerator operation amount”) by the driver as a signal indicating the operating condition of the engine 1, a crank angle sensor 152 is a pulse-shaped detection signal (the control unit 101 calculates the engine speed based on this), and a temperature sensor for detecting the temperature of the engine coolant. In addition to the detection signal from 153, a detection signal from the air flow meter 154 for detecting the intake air amount and a detection signal from the oxygen sensor 155 for detecting the air-fuel ratio of the exhaust are input. The control unit 101 executes a predetermined calculation based on the various signals that are input, and the air-fuel mixture that is formed in the cylinder with respect to the throttle actuator 121 and the injectors 14a to 14d (specifically, drive circuits thereof). A command signal for controlling the air-fuel ratio (hereinafter referred to as “operating air-fuel ratio”) is output. In this embodiment, the air-fuel ratio (exhaust air-fuel ratio) detected by the oxygen sensor 155 is employed as the operating air-fuel ratio.

Next, the configuration of the control system of the engine 1 according to the present embodiment will be described.
2 to 5 show the configuration of the part related to the air-fuel ratio control in the control unit (hereinafter referred to as “ECU”) 101 by functional blocks. The ECU 101 constitutes a “control device” for the engine according to the present embodiment. FIG. 2 shows the overall configuration of the ECU 101. 3 shows the configuration of the fuel injection amount calculation unit B101, FIG. 4 shows the configuration of the target air-fuel ratio calculation unit, and FIG. 5 shows the configuration of the learning correction amount calculation unit B103.

As shown in FIG. 2, the ECU 101 includes a fuel injection amount calculation unit B101, a feedback correction amount calculation unit B102, and a learning correction amount calculation unit B103. The fuel injection amount calculation unit B101 reads the accelerator operation amount APO and the engine speed NE detected as the operating conditions of the engine 1, and calculates the fuel injection amounts Qf of the injectors 14a to 14d based on these operating conditions. It is. The feedback correction amount calculation unit B102 outputs an air-fuel ratio feedback correction amount LAMD to the fuel injection amount calculation unit B101. The feedback correction amount calculation unit B102 inputs a difference (= rABYF-tABYF) between the operating air-fuel ratio rABYF and a corrected target air-fuel ratio tABYF described later, and calculates the feedback correction amount LAMD based on this difference. In the present embodiment, the feedback correction amount calculation unit B102 is configured as a proportional integration controller. The learning correction amount calculation unit B103 inputs the feedback correction amount LAMD from the feedback correction amount calculation unit B102 and outputs the learning correction amount ALPH for feedback control to the fuel injection amount calculation unit B101. The learning correction amount calculation unit B103 searches the learning map based on the driving condition such as the accelerator operation amount APO, reads out and outputs the learning correction amount ALPH stored in the learning area corresponding to the driving condition. Hereinafter, the ECU 101 will be described for each of the blocks B101 to B103.
(Regarding fuel injection amount calculation unit B101)
ECU 101 calculates fuel injection amount Qf in fuel injection amount calculation unit B101 (FIG. 3). The ECU 101 reads the accelerator operation amount APO and the engine speed NE as the operating conditions of the engine 1, and the basic fuel injection amount calculation unit B201 searches the basic fuel injection amount map by the read APO and NE, and performs basic fuel injection. The quantity Qfbase is calculated. The fuel injection amount calculation unit B101 reads the feedback correction amount LAMD and the learning correction amount ALPH. The ECU 101 multiplies the basic fuel injection amount Qfbase by LAMD and ALPH in the multiplication units B202 to B204, The fuel injection amount Qf is calculated by multiplying various correction amounts K corresponding to the time of acceleration or the like.

Qf = Qfbase × ALPH × LAMD × K (1)
(About feedback correction amount calculation unit B102)
In the feedback correction amount calculation unit B102, the target air-fuel ratio (corrected target air-fuel ratio tABYF) read from the next target air-fuel ratio calculation unit (FIG. 4) and the air-fuel ratio (operating air-fuel ratio rABYF) detected by the oxygen sensor 155 are used. Based on this, an air-fuel ratio feedback correction amount LAMD is calculated by proportional-integral calculation.

  ECU 101 calculates a corrected target air-fuel ratio tABYF in a target air-fuel ratio calculation unit (FIG. 4). The ECU 101 reads the accelerator operation amount APO and the engine speed NE, and the basic target air-fuel ratio calculation unit B301 searches the basic target air-fuel ratio map with the read APO and NE to calculate the basic target air-fuel ratio tABYF0. The region determination unit B302 determines a region to which the operating state of the engine 1 belongs based on the accelerator operation amount APO and the like, and outputs the basic target air-fuel ratio tABYF0 as the corrected target air-fuel ratio tABYF when the engine 1 is in steady operation. . The determination by the area determination unit B302 according to the present embodiment is based on calculating the amount of change per unit time of the accelerator operation amount APO and determining that it is in steady operation when this amount is equal to or less than a predetermined amount. On the other hand, when the engine 1 is in a transient operation, the multiplication unit B303 multiplies the basic target air-fuel ratio tABYF0 by a deviation amount ERR, which will be described later, and in the first delay compensation unit B304, the change in the intake air amount is changed to the air-fuel ratio ( The corrected target air-fuel ratio tABYF is calculated and outputted by correcting the delay until it appears in the air-fuel ratio of the exhaust gas). The correction by the first delay compensation unit B304 can be realized by approximating this delay as a primary delay. By changing the time constant of the delay according to the intake air amount rQac or the engine speed NE, approximate accuracy can be maintained regardless of the operating state. The deviation amount ERR is calculated as follows as a target air-fuel ratio correction term for making the basic target air-fuel ratio tABYF0 conform to the change in the actual intake air amount rQac with respect to the operation of the accelerator pedal.

  In order to calculate the deviation amount ERR, the ECU 101 reads the basic fuel injection amount Qfbase, the multiplication unit B305 multiplies the read Qfbase by the basic target air-fuel ratio tABYF0, and the second delay compensation unit B306 operates the accelerator pedal. The target intake air amount tQac is calculated by correcting the change in the intake air amount rQac with respect to the delay. In the correction by the second delay compensation unit B306, in the engine 1 including a turbocharger such as a turbocharger, the output from the multiplication unit B305 is delayed according to the operating characteristics of the turbocharger. Can be realized. In the division unit B307, the ECU 101 divides the intake air amount rQac by the target intake air amount tQac corrected by the second delay compensation unit B306 to calculate a deviation amount ERR.

ERR = rQac / tQac (2)
(About the learning correction amount calculation unit B103)
ECU 101 calculates learning correction amount ALPH for feedback control in learning correction amount calculation unit B103 (FIG. 5). A learning correction amount ALPH storage map (hereinafter referred to as “learning map”) B401 is set in the learning correction amount calculation unit B103, and this learning map B401 is determined in correspondence with each operation state of the engine 1. Each study area is divided. The ECU 101 stores the learning correction amount ALPH obtained based on the feedback correction amount LAMD in the corresponding learning area, or updates the already stored learning correction amount ALPH with the newly obtained learning correction amount ALPH. . The calculation method of the learning correction amount ALPH is already well known, and the learning correction amount ALPH is calculated as having a magnitude that reduces the deviation of the feedback correction amount LAMD from the reference value. In the configuration in which the feedback correction amount LAMD is multiplied by the basic fuel injection amount Qfbase, the learning correction amount ALPH is calculated as an average value of the ratio of the feedback correction amount LAMD to the basic value (= 1). The ECU 101 reads the operating air-fuel ratio rABYF, and the update permission determination unit B403 prohibits updating when the read rABYF is not within a predetermined range and the accuracy of the operating air-fuel ratio detected by the oxygen sensor 155 is not guaranteed. Except when the update is prohibited, the learning correction amount updating unit B402 updates the stored value of the corresponding learning area with the learning correction amount ALPH or the newly obtained learning correction amount ALPH. In addition, the ECU 101 uses the learning correction amount reading unit B404 to search the learning map according to the driving conditions such as the accelerator operation amount APO, reads the learning correction amount ALPH stored in the corresponding learning area, and then calculates the fuel injection amount calculation unit B101. Output to.

Next, the operation of the ECU 101 according to the present embodiment will be described with reference to a time chart.
FIG. 6 is a time chart showing the operation of the ECU 101 during acceleration.

  When the accelerator pedal is depressed at time t1, the basic value of the target air-fuel ratio (basic target air-fuel ratio tABYF0) decreases due to the increase in the accelerator operation amount APO, and accompanying this, the fuel injection amount Qf (basic fuel injection amount Qfbase) Will increase. While the injectors 14a to 14d operate with high responsiveness to the change in the fuel injection amount Qf, the change in the intake air amount rQac has a delay corresponding to the operating characteristics of the turbocharger. A temporary shortage of the intake air amount rQac occurs with respect to Qf, and a drop corresponding to the shortage occurs in the change of the operating air-fuel ratio rABYF (indicated by a two-dot chain line). The ECU 101 calculates a target value (target intake air amount tQac) of the intake air amount according to the basic target air / fuel ratio tABYF0 in the target air / fuel ratio calculation unit (FIG. 4), and also calculates the intake air amount rQac and the target intake air amount. The ratio to tQac (= rQac / tQac) is calculated, and the basic target air-fuel ratio tABYF0 is multiplied by the calculated ratio as the deviation amount ERR, and the corrected target air-fuel ratio tABYF obtained as a result is used for the calculation of the feedback correction amount LAMD. To do. The corrected target air-fuel ratio tABYF obtained in this way is that the target intake air amount tQac is in accordance with the change in the basic target air-fuel ratio tABYF0, and the intake air amount rQac is reflected in the calculation through the divergence amount ERR. Therefore, the intake air amount rQac is changed in accordance with a transient change under an actual driving condition. The ECU 101 calculates a difference δ1 between the operating air-fuel ratio rABYF and the corrected target air-fuel ratio tABYF, calculates a feedback correction amount LAMD based on the difference δ1, and corrects the fuel injection amount Qf by the calculated LAMD. Further, the ECU 101 searches the learning map according to the driving conditions such as the accelerator operation amount APO, calculates the learning correction amount ALPH, and stores it in the learning map by the feedback correction amount LAMD obtained during the air-fuel ratio feedback control. The learning correction amount ALPH being updated is sequentially updated.

  In the present embodiment, the accelerator sensor 151 constitutes an “accelerator operation amount detection means”, the oxygen sensor 155 constitutes an “operating air-fuel ratio detection means”, and the air flow meter 154 constitutes an “operating state quantity detection means”. The Further, in the ECU 101, the basic target air-fuel ratio calculation unit B301 functions as a “target air-fuel ratio calculation unit”, and the division unit B307 functions as a “deviation amount detection unit”. The multiplication unit B303 and the first delay compensation The function as “target air-fuel ratio correction means” is realized by the part B304, and the function as “control command value calculation means” is realized by the fuel injection amount calculation part B101, the feedback correction amount calculation part B102, and the learning correction amount calculation part B103. . The multiplication unit B305 and the second delay compensation unit B306 function as a “target intake air amount calculation unit”, the region determination unit B302 functions as an “region determination unit”, and the feedback correction amount calculation unit B102 “ The function as “feedback correction amount calculation means”, the function as “learning correction amount storage means” by the learning map B401, and the function as “learning correction amount update means” by the learning correction amount update unit B402 are the update permission determination unit. The function as “update prohibition means” is realized by B403.

According to this embodiment, the following effects can be obtained.
In the present embodiment, the intake air amount rQac is detected as the “operating state amount” of the engine 1, the deviation amount ERR of the detected rQac with respect to the target value (target intake air amount tQac) is calculated, and the calculated ERR is calculated. By multiplying, the target air-fuel ratio (basic target air-fuel ratio tABYF0) is corrected, and the corrected target air-fuel ratio tABYF used for calculating the fuel injection amount Qf is calculated.

  Here, the actual change in the intake air amount rQac has a delay with respect to the accelerator operation. Due to this delay, the change in the operating air-fuel ratio rABYF causes a drop. With respect to this drop, the target air-fuel ratio tABYF Without any compensation, the fuel injection amount Qf was calculated from the feedback correction amount LAMD according to the difference δ2 (FIG. 6) between the operating air-fuel ratio rABYF and the target air-fuel ratio (basic target air-fuel ratio tABYF0) without compensation. In this case, the fuel injection amount is caused by the temporary deviation of the operating air-fuel ratio rABYF due to the delay of the intake air amount rQac, although the proper amount of fuel is actually injected by the injectors 14a to 14d. Unnecessary weight reduction correction is applied to Qf.

  On the other hand, in the present embodiment, the target intake air amount tQac corresponds to the target air-fuel ratio (basic target air-fuel ratio tABYF0) and shows a change corresponding to the target air-fuel ratio tABYF0. Since the intake air amount rQac is reflected in the correction through the divergence amount ERR, the target air-fuel ratio (corrected target air-fuel ratio tABYF) obtained by the correction is a transient of the intake air amount rQac under actual operating conditions. It will be in line with changes.

  Therefore, according to the present embodiment, based on the target air-fuel ratio corrected by the deviation amount ERR (corrected target air-fuel ratio tABYF), the feedback correction amount LAMD can be calculated without excess or deficiency even during transient operation. Control can be realized with higher accuracy.

  According to this embodiment, since the feedback correction amount LAMD can be calculated even during transient operation, the learning correction amount ALPH is calculated and stored (updated) not only during steady operation but also during transient operation. It is possible to expand the learning area where the feedback correction amount is learned and to ensure the learning frequency.

  The case where the intake air amount rQac is employed as the “operating state amount” of the engine 1 has been described above. However, according to the present invention, the pressure of the intake air or the outside air can be adopted as the “operating state quantity”. In this case, the corrected target air-fuel ratio tABYF is calculated by installing a pressure sensor as an “operating state amount detecting means” in the intake passage 11 and calculating a ratio between the pressure of the intake air detected by the pressure sensor and the target pressure. By multiplying this by the target air-fuel ratio (basic target air-fuel ratio tABYF0) as the “deviation amount” ERR.

  Further, in the above, one learning map B401 is employed for storing the learning correction amount ALPH, and the learning correction amount ALPH is stored in this one learning regardless of whether the engine 1 is in steady operation or transient operation. The case where the information is stored in the map B401 has been described. However, the learning map B401 may be switched between the steady operation and the transient operation, and the learning correction amount ALPH may be switched in each case.

Configuration of engine according to one embodiment of the present invention Configuration of control unit according to the embodiment Configuration of fuel injection amount calculation unit of control unit Configuration of target air-fuel ratio calculation unit of control unit Configuration of learning correction amount calculation unit of control unit Time chart showing the operation of the control unit during acceleration

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Engine, 11 ... Intake passage, 12 ... Throttle valve, 121 ... Throttle actuator, 13 ... Surge tank, 14a-14d ... Injector, 15 ... Fuel supply passage, 21a-21d ... Spark plug, 31 ... Exhaust passage, 32 ... Catalytic converter 101 ... Control unit 151 ... Accelerator sensor 152 ... Crank angle sensor 153 ... Cooling water temperature sensor 154 ... Air flow meter 155 ... Oxygen sensor B101 ... Fuel injection amount calculation unit B102 ... Feedback correction amount calculation Part, B103 ... learning correction amount calculation part.

Claims (12)

An accelerator operation amount detection means for detecting the driver's accelerator operation amount;
Target air-fuel ratio calculating means for calculating a target air-fuel ratio of the air-fuel mixture based on the accelerator operation amount detected by the accelerator operation amount detecting means;
An operating air-fuel ratio detecting means for detecting an actual operating air-fuel ratio;
An operating state quantity detection means for detecting an engine intake air quantity or an operating state quantity correlated therewith as an engine operating state quantity;
Based on the operating state quantity detected by the operating state quantity detecting means, a deviation amount of the detected operating state quantity from a target value of the operating state quantity corresponding to the target air / fuel ratio calculated by the target air / fuel ratio calculating means is calculated. A deviation amount detecting means for detecting;
When the change amount per unit time of the accelerator operation amount exceeds a predetermined amount , the corrected target air-fuel ratio is calculated by correcting the calculated target air-fuel ratio based on the deviation amount detected by the deviation amount detecting means. Target air-fuel ratio correction means for
Control command value calculation for calculating a control command value for controlling the air-fuel ratio of the air-fuel mixture based on the corrected target air-fuel ratio calculated by the target air-fuel ratio correcting means and the operating air-fuel ratio detected by the operating air-fuel ratio detecting means And an engine control device comprising the means. 2. The engine control device according to claim 1, further comprising target operating state quantity calculating means for calculating a target value of the operating state quantity based on the target air / fuel ratio calculated by the target air / fuel ratio calculating means. A target intake air amount calculating means for calculating a target intake air amount that is a target value of the intake air amount as the operating state quantity based on the target air / fuel ratio calculated by the target air / fuel ratio calculating means;
2. The divergence amount detection unit detects a divergence amount of the intake air amount as the detected operating state amount with respect to the target intake air amount calculated by the target intake air amount calculation unit as the divergence amount. Engine control device. The deviation amount detection means calculates a ratio between the intake air amount detected by the operating state quantity detection means and the calculated target intake air amount as the deviation amount,
4. The engine control apparatus according to claim 3, wherein the target air-fuel ratio correcting unit calculates the corrected target air-fuel ratio by multiplying the calculated target air-fuel ratio by a ratio as the deviation amount. The target intake air amount calculation means corrects a delay in the change in the intake air amount with respect to the driver's accelerator operation on the basic value of the target intake air amount according to the calculated target air-fuel ratio, so that the target intake air amount The engine control device according to claim 3 or 4, wherein the amount is calculated. The target air-fuel ratio correcting means corrects a delay in change in the operating air-fuel ratio detected by the operating air-fuel ratio detecting means with respect to the intake air amount detected by the operating state quantity detecting means, and sets the corrected target air-fuel ratio. The engine control device according to claim 3, wherein the engine control device is calculated. It further includes region determining means for determining a region to which the operating state of the engine belongs,
The control command value calculating means includes
When the region determining means determines that the engine belongs to the first region, the control command value is calculated based on the calculated corrected target air-fuel ratio and the detected operating air-fuel ratio,
When the region determining means determines that the engine belongs to a second region different from the first region, it is based on the target air-fuel ratio calculated by the target air-fuel ratio calculating unit instead of the corrected target air-fuel ratio. The engine control device according to claim 1, wherein the control command value is calculated. The region determination means determines whether the engine belongs to a predetermined transient region as the first region or a steady region as the second region set as a region other than the predetermined transient region. The engine control device according to claim 7. The control command value calculating means includes
Feedback correction amount calculating means for calculating an air-fuel ratio feedback correction amount based on the calculated corrected target air-fuel ratio and the detected operating air-fuel ratio;
Learning correction amount storage means for storing a learning correction amount of the control command value;
Learning correction amount updating means for correcting the learning correction amount stored in the learning correction amount storage means based on the feedback correction amount calculated by the feedback correction amount calculating means and updating the learning correction amount as a new learning correction amount; Comprising and including
Reading the stored learning correction amount,
The control command value is calculated by correcting the basic value of the control command value according to the accelerator operation amount detected by the accelerator operation amount detection means based on the calculated feedback correction amount and the read learning correction amount. The engine control device according to claim 1. In the learning correction amount storage means, a learning area for storing the learning correction amount is determined corresponding to each engine operating state, and the learning correction amount is stored in one learning area for each of the transient and steady operating states. The engine control device according to claim 9, which is configured as a storage unit. The control command value calculating means further includes an update prohibiting means for prohibiting the learning correction amount updating means from updating the learning correction amount when the operating air / fuel ratio detected by the operating air / fuel ratio detecting means is outside a predetermined range. The engine control apparatus according to 9 or 10, comprising the engine. The engine control device according to claim 1, wherein the control command value is a fuel supply amount to the engine.

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