JP2808214B2 - Air-fuel ratio control device for internal combustion engine with evaporative fuel control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal combustion engine having an evaporative fuel control device for temporarily storing evaporative fuel in a fuel tank and controlling the amount of intake into an intake system of the engine while controlling the amount of intake under predetermined engine operating conditions. The present invention relates to a device for controlling an air-fuel ratio in an engine.

[0002]

2. Description of the Related Art As a measure to regulate the amount of evaporative fuel generated from a fuel tank, the evaporative fuel is temporarily adsorbed by an adsorber called a canister, and the adsorbed fuel is suctioned under a predetermined engine operating state. A system has been considered in which the fuel is sucked (purged) into the intake system for combustion treatment. Although the system itself is mounted on an actual vehicle, a recent measure is to start purging from a state in which the canister is filled with evaporative fuel so as to reliably prevent the evaporative fuel from being released from the canister. It is a harsh condition that it is required to perform combustion treatment and keep the emission amount within the regulation value.

[0003]

When such a large amount of fuel vapor is purged, the intake of the fuel vapor causes a large deviation in the air-fuel ratio in normal air-fuel ratio control.
To increase the emission of various pollutant components, it is necessary to control the air-fuel ratio appropriately by reducing the amount of fuel supplied in proportion to the amount of evaporative fuel inhaled. Has not been made.

For example, conventionally, in an internal combustion engine having an electronically controlled fuel injection device having an air-fuel ratio feedback control function, Japanese Patent Application Laid-Open Nos.
An air-fuel ratio learning control device such as that disclosed in Japanese Patent Publication No. 190142 is adopted. This is because a basic fuel injection amount calculated from parameters of the engine operating state related to the amount of air taken into the engine (for example, the engine intake air flow rate and the engine speed) is a signal from an O ₂ sensor provided in the engine exhaust system. The air-fuel ratio is corrected by an air-fuel ratio feedback correction coefficient set by proportional / integral control and the like to calculate the fuel injection amount, and the air-fuel ratio is feedback-controlled to the target air-fuel ratio. The learning value is determined by learning the deviation from the reference value for each of the operating regions classified according to the engine operating state, and in setting the fuel injection amount, the basic fuel injection amount is corrected by the learning value, and the air-fuel ratio feedback correction coefficient The base air-fuel ratio obtained by the fuel injection amount calculated without correction by the air-fuel ratio is adjusted to the target air-fuel ratio. Tsu in click control is intended for calculating the fuel injection amount is corrected by further feedback correction coefficient so.

According to this, the deviation of the base air-fuel ratio from the target air-fuel ratio due to variations (initial variations and deterioration) of components (air flow meters and fuel injection valves) can be eliminated. It is possible to eliminate the delay in following the feedback control during operation,
When the air-fuel ratio feedback control is stopped, a desired air-fuel ratio can be accurately obtained.

However, if the learning control of such a conventional air-fuel ratio learning control device for an internal combustion engine is used as it is under the condition that the evaporated fuel is purged, first, the fuel supply amount is increased by the amount of the intake of the evaporated fuel. The air-fuel ratio feedback correction coefficient is greatly reduced to maintain the air-fuel ratio at the target air-fuel ratio. Then, the learning value decreases so as to eliminate the change of the feedback correction coefficient. That is, at the time of convergence, learning is performed such that the fuel amount obtained by adding the evaporated fuel intake amount to the basic fuel injection amount becomes an amount corresponding to the target air-fuel ratio.

After the erroneous learning is performed, when the purging of the evaporated fuel is stopped, in the same operation region determined by the load, the rotation speed, and the like of the engine, the intake amount of the evaporated fuel is learned and greatly reduced. Since the fuel injection amount is set using the learning value, the air-fuel ratio becomes significantly lean until the feedback correction works effectively, and NOx
Etc. will increase the emission amount. Also, if the purge is performed after the fuel vapor is learned without being purged,
This time, the learning value is too large because the learning for the purge is not performed, which causes the air-fuel ratio to be enriched, and the HC and CO emissions increase.

The present invention has been made in view of such a conventional problem. By learning the air-fuel ratio corresponding to the purge of the evaporated fuel, it is possible to maintain a stable air-fuel ratio regardless of the presence or absence of the purge. An object of the present invention is to provide an air-fuel ratio control device for an internal combustion engine with an evaporative fuel control device as described above.

[0009]

For this reason, a first air-fuel ratio control apparatus for an internal combustion engine with an evaporative fuel control apparatus according to the present invention has the requirements shown in FIG. Explaining each requirement, the evaporative fuel control device A temporarily stores the evaporative fuel in the fuel tank and inhales the stored evaporative fuel into the intake system of the engine while controlling the intake amount under predetermined engine operating conditions. Let it.

The operating state detecting means B detects an operating state of the engine, such as a load and a rotation speed. The air-fuel ratio detecting means C detects the air-fuel ratio of the air-fuel mixture supplied to the engine by detecting the oxygen concentration or the like in the exhaust gas. The air-fuel ratio basic control value setting means D includes:
The basic control value of the air-fuel ratio is set based on the load, rotation speed, and the like of the engine detected by the operating state detecting means.

Air-fuel ratio feedback correction value setting means E
Sets an air-fuel ratio feedback correction value for increasing or decreasing the air-fuel ratio control value so that the air-fuel ratio detected by the air-fuel ratio detection means approaches a target value. The air-fuel ratio learning value storage means F stores a learning value for correcting the basic control value of the air-fuel ratio for each operation region.

The air-fuel ratio learning value updating means G compares an average value of the air-fuel ratio feedback correction value at the time of convergence with a reference value for each of the operating regions, and decreases the deviation between the average value and the reference value. The learning value of the corresponding operating region stored in the air-fuel ratio learning value storage means is corrected and updated. The air-fuel ratio control value setting means H corrects a value obtained by correcting a basic control value of the air-fuel ratio set by the basic control value with a learning value of a corresponding operating region retrieved from the air-fuel ratio learning value storage means. The final air-fuel ratio control value is set by correcting with the correction value.

The engine load and the control value of the intake amount of the evaporated fuel into the intake system are included as parameters for determining the operating range in which the learned value of the air-fuel ratio learned value storage means F is stored. . Further, the second air-fuel ratio control device for an internal combustion engine with an evaporative fuel control device according to the present invention includes the above-mentioned respective means A to E, and stores a learning value from which the influence of the intake of the evaporative fuel has been removed. An air-fuel ratio learned value storage means F ′ separately provided with a map and a map for storing a learned value only by the intake of the evaporated fuel; It is divided into a learning value from which the influence has been removed and a learning value only by inhalation of the evaporated fuel,
An air-fuel ratio learning value updating unit G ′ having a function of correcting and updating the learning value stored in the corresponding map of the air-fuel ratio learning value storage unit, and a map of the air-fuel ratio learning value storage unit. Air-fuel ratio control value setting means H ′ having a function of setting an air-fuel ratio control amount using a learning value obtained by summing the searched learning values.

A third aspect of the present invention relates to an air-fuel ratio control device for an internal combustion engine with an evaporative fuel control device, which is provided with each of the means A to E. The air-fuel ratio learning value updating means H "having a function of correcting and updating the learning value using the correction rate variably set accordingly is provided.

[0015]

The amount of purge of the evaporative fuel to the intake system is controlled by the evaporative fuel control device.
The air-fuel ratio feedback correction value is set in a direction to suppress the air-fuel ratio from being enriched. Then, the air-fuel ratio learning value updating means performs learning to decrease the deviation between the determined air-fuel ratio feedback correction value and the reference value, and adds the purge fuel equivalent value to the basic air-fuel ratio control value. A learning value is obtained such that the calculated value approaches the target air-fuel ratio equivalent value.

Thereafter, in the first air-fuel ratio control device, the learning value is determined by the load value representing the engine operation state of the air-fuel ratio learning value storage means and the control value of the evaporated fuel purge amount. The learning value is updated and stored for each area. By storing the learned value in association with the purge control value of the evaporated fuel in this way, even if the evaporated fuel purge amount changes, the learned value in a region corresponding to the purge amount is used and the final value is used. As a result of setting the air-fuel ratio control value, good air-fuel ratio control that avoids the influence of the purge is performed.

Further, in the second air-fuel ratio control device,
The learning value learned in the same manner as above is divided into a learning value obtained by removing the influence of the evaporative fuel in accordance with the evaporative fuel purge control value and a learning value obtained only by the intake of the evaporative fuel, and updated and stored in separate maps. In setting the air-fuel ratio control amount, a learning value obtained by adding the learning values from these maps is used. In this case, in addition to the load as a parameter for determining the area of each map, even if a rotational speed or the like is added, highly accurate learning can be performed without significantly increasing the storage capacity, and the air-fuel ratio control that avoids the influence of the purge can be performed. Accuracy is further improved.

Further, learning for purging the evaporated fuel is as follows.
Since the change of the adsorption / desorption of the canister that adsorbs and stores the evaporated fuel may be fast, it is necessary to update the learning value with a large correction rate (time constant) corresponding to the change. On the other hand, the variation of the parts from which the influence of the purge of the fuel vapor has been removed is a very slow change, so that it is better to update the learning value with a sufficiently small correction rate.

Therefore, in the third air-fuel ratio control apparatus, the correction rate is set to be larger when the purge is performed in accordance with the presence or absence of the purge of the evaporated fuel or the ratio of the purge amount, and when the purge amount is larger, the correction rate is set to be larger. By learning,
The accuracy of the air-fuel ratio control can be improved by setting the progress speed of the learning to be appropriate.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 2 showing a configuration of an embodiment, an intake passage 12 of an engine 11 is provided with an air flow meter 13 for detecting an intake air flow rate Q and a throttle valve 14 for controlling the intake air flow rate Q in conjunction with an accelerator pedal. In the downstream manifold part, an electromagnetic fuel injection valve as a fuel supply means for each cylinder
15 are provided.

The fuel injection valve 15 is driven to open by an injection pulse signal from a control unit 16 containing a microcomputer to inject and supply fuel. In addition, agencies
A water temperature sensor 17 for detecting a cooling water temperature Tw in the cooling jacket 11 is provided. On the other hand, the exhaust passage 18 is provided with an air-fuel ratio sensor 19 as an air-fuel ratio detecting means for detecting the air-fuel ratio of the intake air-fuel mixture by detecting the oxygen concentration in the exhaust gas at the manifold collecting portion. A three-way catalyst 20 is provided as an exhaust gas purifying catalyst for purifying by oxidizing CO and HC in exhaust gas and reducing NO _X.

A distributor (not shown in FIG. 2) includes a crank angle sensor 21. The crank angle sensor 21 outputs a crank unit angle signal in synchronization with the engine rotation for a certain period of time. Alternatively, the period of the crank reference angle signal is measured to detect the engine speed N. Incidentally, the air flow meter 13, the water temperature sensor 17, the crank angle sensor 21 and the like correspond to the operating state detecting means.

Next, the fuel supply system will be described. A fuel pump 23 is mounted in a fuel tank 22 and the fuel pump
The fuel fed from 23 is adjusted to a predetermined pressure through a fuel supply passage 25 with a pressure regulator 24 interposed, and is supplied to the fuel injection valve 15. Excess fuel from the pressure regulator 24 is returned to the fuel tank 22 via a return fuel passage 26.

The fuel vapor stored in the upper space of the fuel tank 22 is supplied to a fuel vapor passage 28 provided with a check valve 27.
Through the canister 29. The evaporated fuel temporarily adsorbed in the canister 29 is sucked into the intake passage 12 downstream of the throttle valve 14 through a purge passage 31 provided with a purge control valve 30 under a predetermined operating condition. Here, the purge control valve 30
Is set by the control unit 16 based on the operating state of the engine, and the set opening control signal is input from the control unit 16 and controlled.

Next, the air-fuel ratio control routine by the control unit 16 will be described with reference to the flowcharts of FIGS. FIG. 3 shows a fuel injection amount setting routine, which is performed at predetermined intervals (for example, every 10 ms). In step (denoted by S in the figure) 1, the air flow meter 13
Air flow rate Q detected by the crank angle sensor
Based on the engine rotational speed N calculated on the basis of the signal from 21, the basic fuel injection quantity T _P corresponding to the intake air amount per unit rotation is calculated by the following equation. Basic fuel injection amount T
_P corresponds to the basic control value of the air-fuel ratio. Therefore, the function of step 1 corresponds to the air-fuel ratio basic control value setting means.

T _P = K × Q / N (K is a constant) In step 2, various correction coefficients COEF are set based on the cooling water temperature Tw detected by the water temperature sensor 17. In step 3, a feedback correction coefficient α set by a feedback correction coefficient setting routine to be described later and a learning value α _L of a corresponding operation region stored in a map of a RAM to be described later are read. Learning value and the map of the RAM of the amount example basic fuel injection quantity T _P represents the load of the engine the opening control value of the purge control valve 30 PA for each operating region surrounded by lattice axes to parameter-data α _L is stored, and the map corresponds to an air-fuel ratio learning value storage unit.

In step 4, a voltage correction value T _S is set based on the battery voltage value. This is for correcting a change in the injection flow rate of the fuel injection valve 15 due to the battery voltage fluctuation. In step 5, the final fuel injection amount T _I
Is calculated according to the following equation. The final fuel injection amount T _I corresponds to the final air-fuel ratio control value, and therefore, the function of step 5 corresponds to the air-fuel ratio control value setting means.

T _I = T _P × COEF × α × α _L + T _S } or T _I = T _P × COEF × (α + α _L ) + T _S } In step 6, the calculated fuel injection valve T _I is stored in an output register. Set to. Accordingly, at a predetermined fuel injection timing synchronized with the engine rotation, a drive pulse signal having a pulse width of the calculated fuel injection amount T _I is given to the fuel injection valve 15 to perform fuel injection.

Next, the air-fuel ratio feedback correction coefficient setting routine will be described with reference to the flowchart of FIG. This routine is executed in synchronization with the engine rotation. This air-fuel ratio feedback correction coefficient setting routine corresponds to air-fuel ratio feedback correction value setting means. In step 11,
It is determined whether or not the operating condition is such that the air-fuel ratio feedback control is performed. If the operating conditions are not satisfied, this routine ends. In this case, the feedback correction coefficient α is clamped to the value at the end of the previous feedback control or a fixed reference value, and the feedback control is stopped.

In step 12, the signal voltage V _O2 from the air-fuel ratio sensor 19 is input. In step 13, the signal voltage _VO2 input in step 12 is compared with a reference value SL corresponding to a target air-fuel ratio (stoichiometric air-fuel ratio) to determine whether the air-fuel ratio is rich or lean. judge. When the air-fuel ratio is lean ( _VO2 <SL), the process proceeds to step 14, and it is determined whether or not the rich-to-lean inversion is performed (immediately after the inversion).
To step 16 to update the air-fuel ratio feedback correction coefficient α to a value obtained by adding the predetermined proportional amount P _L to the current value. It is updated with the value obtained by adding the I _L.

On the other hand, if it is determined in step 13 that the air-fuel ratio is rich (V _O2 > SL), the process proceeds to step 17 and the lean-to-lean operation is performed.
It is determined whether the time of the rich inversion (after inversion) at the time of reversing the flow proceeds to step 18, updates the air-fuel ratio feedback correction coefficient α by a value obtained by subtracting from the current value of the predetermined proportional portion P _R, when inverted except updates with the air-fuel ratio feedback correction coefficient value obtained by subtracting from the current value of the predetermined integral portion I _L of α proceeds to step 19.

FIG. 5 shows a routine for controlling the opening of the purge control valve 30. In the figure, in step 41, an opening control value PA in a corresponding operating region is searched from a map of opening control values set in advance based on the engine load (basic fuel injection amount _TP ) and the rotational speed N. In step 42, the searched opening control value PA is output to the purge control valve 30 to control the opening.

Next, a routine for updating the learning value of the air-fuel ratio will be described with reference to the flowchart of FIG. This learning value updating routine corresponds to an air-fuel ratio learning value updating unit. In step 21, the operating area for storing a learned value alpha _L of the air-fuel ratio is determined whether the change from the previous area. In the present embodiment, the operating region for storing the learned value alpha _L as shown in FIG. 6 (B), the opening degree of the load and the purge control value, i.e. the purge control valve 30 such as a basic fuel injection quantity T _P Two parameters including the control value PA are determined as lattice axes. If it is determined that the areas are not the same area, the process proceeds to step 22 to reset a count value _CMAP described later to 0, and then ends this routine. Step 21
If it is determined in the above that the operating range is the same, the process proceeds to step 23, where it is determined whether the air-fuel ratio is rich _or lean, or not. The count value C _MAP representing the number of inversions is incremented by 1, and the step is performed when, for example, C _MAP = 3.
From step 25, the process proceeds to step 26 to find a deviation (α-1) between the current air-fuel ratio feedback correction coefficient α and the reference value 1,
temporarily stored as α _1. If it is determined in step 23 that the rotation is not reversed, this routine ends.

When C _MAP ≧ 4, step 25
From step 27 to the deviation (α-1) of the air-fuel ratio feedback correction coefficient α from the reference value 1 by Δα
Store as ₂ temporarily. In step 28, it obtains a deviation [Delta] [alpha] ₁ between the air-fuel ratio feedback correction coefficient α and the reference value 1 previously obtained, the average value [Delta] [alpha] _M with deviation [Delta] [alpha] ₂ obtained in the step 27.

Next, the routine proceeds to step 29, where the learning value α _L stored corresponding to the current operation area is read. Proceeding to step 30, _a new learning value α _L is added by adding a predetermined ratio Ka to the average value Δα _M of the deviation between the air-fuel ratio feedback correction coefficient α and the reference value 1 to the current learning value α _L according to the following equation. To calculate the learning value α _L of the same area on the RAM.
Modify and rewrite the data in

Thereafter, in step 31, for the next learning,
Substituting Δα ₂ to Δα _1. In this way, learning is performed for each operation region determined by using the control value PA of the purge amount of the evaporated fuel as a parameter in addition to the load (basic fuel injection amount _TP ) representing the operating state of the engine, and the learning value α _{Since L} is updated, stable air-fuel ratio control can be performed regardless of the purge amount.

However, in the above-described embodiment, the engine speed N is not used as a parameter for determining the operating region in which learning is performed. Therefore, it is conceivable to improve the learning accuracy by using the engine rotation speed N as a parameter. However, the learning value is stored in a four-dimensional map based on three parameters of the engine load, the rotation speed, and the amount of fuel vapor intake. It is not realistic because the storage capacity is enormous.

Therefore, an embodiment of the second air-fuel ratio control device will be described below in which learning with sufficiently high precision can be performed while increasing the storage capacity as much as possible. The system configuration is the same as that of FIG. 2 and only the routine for updating the air-fuel ratio learning value is different, so the learning value updating routine will be described. In step 51, the operation region where the operating area similar learning value in step 21 is stored to store the learning value alpha _L of the air-fuel ratio is determined whether the change from the previous area, the learning in the present embodiment The value α _L is stored as α _L1 and α _L2 for each map according to the presence or absence of the effect of the evaporated fuel, as described later. The operating region where these α _L1 and α _L2 are stored is based on the basic fuel injection amount T _P and the engine speed N are classified as parameters.

Steps 52 to 58 correspond to the above steps.
The description is omitted because it is the same as 22 to step 28. In step 59, the average value of the deviation Δα _M is converted into a deviation Δα _M1 caused only by component variations that are not affected by the suction of the evaporated fuel and a deviation Δα _M2 caused only by the suction of the evaporated fuel in accordance with the purge amount of the evaporated fuel. To divide. Specifically, it is obtained by the following equation using the opening control amount PA of the purge control valve 30.

Δα _M1 = (1−PA) Δα _M Δα _M2 = PAΔα _M Next, the routine proceeds to step 60, where the learning value α _L1 stored in the corresponding operation area of the first map in the RAM is calculated. Learning value α stored in the corresponding driving area of the second map
_{Read L2} . Here, the first map stores a learning value α _L1 estimated to be caused by a substantial component variation excluding the effect of the purge of the evaporated fuel, and a second map.
In the map, the learning value α _L2 estimated to be generated by the purge of the evaporated fuel is stored.

Further, the routine proceeds to step 61, where the deviations Δα _M1 and Δα _M1 corresponding to the learning values α _L1 and α _L2 respectively correspond to the learning values α _L1 and α _L2.
New learning values α _{L1 and} α _L2 are calculated by adding α _M2 by predetermined ratios k ₁ and k ₂ (<1) _{, and} the data of the learning values α _{L1 and} α _L2 of the same area of each map are calculated. Is modified and rewritten. After this, at step 62 for the next learning,
Substituting Δα ₂ to Δα _1.

When setting the fuel injection amount, a value obtained by adding the two learning values α _{L1 and} α _L2 is used as the learning value _L used in step 5 of FIG. In addition, the change in the adsorption / desorption of the evaporated fuel of the canister 29 which adsorbs and stores the evaporated fuel is fast, and the change in the air-fuel ratio deviation accompanying this is fast.
Therefore, a large correction rate (time constant) corresponding to the change
It is required that the learning value be updated to improve the responsiveness.
On the other hand, since the deviation of the air-fuel ratio due to the variation of the parts from which the effect of the purge of the evaporated fuel has been removed is a very slow change, it is better to update the learning value with a sufficiently small correction rate.

Therefore, as an embodiment of the air-fuel ratio control device for an internal combustion engine with a third evaporative fuel control device, the update ratios k ₁ and k ₂ in step 61 in FIG.
For, by setting a sufficiently large value as compared to the update rate k ₂ of the learning value amount alpha _L2 updates ratio k ₁ of the learning value amount alpha _L1 by the component variations due the influence of the fuel vapor, to ensure responsiveness .

Alternatively, FIG. 6A showing the first embodiment.
In step 29 'before step 30 in the purge control valve
Reads the correction factor K _a variable set learning values in accordance with 30 of the opening control value PA, be configured as to update the learning value alpha _L with correction factor K _a according to the PA Good.
Here, the correction factor K _a is because it is set larger opening control value PA is larger, it is possible to enhance the responsiveness enough to accelerate the learning progress rate amount of purged evaporative fuel is increased.

[0045]

As described above, according to the first air-fuel ratio control apparatus for an internal combustion engine with an evaporative fuel control apparatus according to the present invention, the parameter for determining the area in which the learned value of the air-fuel ratio is updated and stored is determined. Since the configuration includes the engine load and the purge control value of the evaporated fuel, learning that avoids the influence of the purge of the evaporated fuel is performed. As a result of the learning, good air-fuel ratio control can be performed regardless of the purge of the evaporated fuel. .

According to the second air-fuel ratio control apparatus for an internal combustion engine with an evaporative fuel control apparatus according to the present invention, the load is stored as a parameter for determining the area of each map, in addition to the load, in addition to the rotational speed. Without significantly increasing the capacity,
Highly accurate learning can be performed, and the accuracy of air-fuel ratio control that avoids the influence of purging can be further enhanced. Further, the third aspect of the present invention
According to the air-fuel ratio control device of the internal combustion engine with the evaporative fuel control device, since the correction rate of the learning value is variably set according to the purge control value of the evaporative fuel, the responsiveness is improved with respect to a purge with a large change. Learning is performed, and stable air-fuel ratio control can be performed.

[Brief description of the drawings]

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

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

FIG. 3 is a flowchart showing a fuel injection amount setting routine of the embodiment.

FIG. 4 is a flowchart showing an air-fuel ratio feedback correction coefficient setting routine of the embodiment.

FIG. 5 is a flowchart showing an evaporative fuel purge control routine of the embodiment.

FIG. 6 is a flowchart showing an air-fuel ratio learning value setting routine of the embodiment and a map for storing learning values;

FIG. 7 is a flowchart showing an air-fuel ratio learning value setting routine common to the second embodiment and the third embodiment of the present invention.

[Explanation of symbols]

 11 Engine 13 Air flow meter 15 Fuel injection valve 16 Microcomputer 19 Air-fuel ratio sensor 21 Crank angle sensor 22 Fuel tank 28 Evaporated fuel passage 29 Canister 30 Purge control valve

Continuation of front page (56) References JP-A-60-65245 (JP, A) JP-A-61-112755 (JP, A) JP-A-63-41632 (JP, A) JP-A-63-131843 (JP) JP-A-1-273850 (JP, A) JP-A-2-67439 (JP, A) JP-A-2-130240 (JP, A) JP-A-2-248638 (JP, A) (58) Field surveyed (Int. Cl. ⁶ , DB name) F02D 41/14 310 F02D 45/00 F02M 25/08 301

Claims (3)

(57) [Claims] A fuel tank for temporarily storing fuel vapor;
Operating state detecting means for detecting the engine operating state; an operating state detecting means for detecting the engine operating state; and an operating state detecting means for supplying the stored evaporative fuel to the engine intake system while controlling the amount of suction under predetermined engine operating conditions. Air-fuel ratio detecting means for detecting the air-fuel ratio of the air-fuel mixture, air-fuel ratio basic control value setting means for setting a basic air-fuel ratio control value based on the detected engine operating state, and a target air-fuel ratio Air-fuel ratio feedback correction value setting means for setting an air-fuel ratio feedback correction value for increasing / decreasing the control value of the air-fuel ratio so as to approach the learning value, and a learning value for correcting the basic control value of the air-fuel ratio for each operation region. And an air-fuel ratio learning value storage means for storing an average value of the air-fuel ratio feedback correction value at the time of convergence with a reference value for each of the operation regions, and decreasing the air-fuel ratio in a direction to reduce a deviation between the average value and the reference value. Burning Air-fuel ratio learning value updating means for correcting and updating the learning value of the corresponding operation area stored in the learning value storage means, and correcting the basic control value of the set air-fuel ratio with the learning value of the corresponding engine operation area. An air-fuel ratio control value setting unit that corrects the air-fuel ratio with the air-fuel ratio feedback correction value to set a final air-fuel ratio control value. An evaporative fuel control device comprising a load of an engine and a control value of a suction amount of evaporative fuel to the intake system as parameters for determining an operation region in which a learning value of the learning value storage means is stored. Air-fuel ratio control device for an internal combustion engine with an engine. 2. A fuel tank for temporarily storing fuel vapor in a fuel tank,
Operating state detecting means for detecting the engine operating state; an operating state detecting means for detecting the engine operating state; and an operating state detecting means for supplying the stored evaporative fuel to the engine intake system while controlling the amount of suction under predetermined engine operating conditions. Air-fuel ratio detecting means for detecting the air-fuel ratio of the air-fuel mixture, air-fuel ratio basic control value setting means for setting a basic air-fuel ratio control value based on the detected engine operating state, and a target air-fuel ratio Air-fuel ratio feedback correction value setting means for setting an air-fuel ratio feedback correction value for increasing / decreasing the control value of the air-fuel ratio so as to approach the learning value, and a learning value for correcting the basic control value of the air-fuel ratio for each operation region. And an air-fuel ratio learning value storage means for storing an average value of the air-fuel ratio feedback correction value at the time of convergence with a reference value for each of the operation regions, and decreasing the air-fuel ratio in a direction to reduce a deviation between the average value and the reference value. Burning Air-fuel ratio learning value updating means for correcting and updating the learning value of the corresponding operation area stored in the learning value storage means, and correcting the basic control value of the set air-fuel ratio with the learning value of the corresponding engine operation area. An air-fuel ratio control value setting unit that corrects the air-fuel ratio with the air-fuel ratio feedback correction value to set a final air-fuel ratio control value. The learning value storage means includes a map for storing a learning value obtained by removing the influence of the evaporative fuel suction and a map for storing a learning value only by the suction of the evaporative fuel. Divides the corrected learning value into a learning value in which the influence of the evaporative fuel is removed and a learning value only by the inhalation of the evaporative fuel in accordance with the ratio of the amount of intake of the evaporative fuel. Corresponding The air-fuel ratio control value setting means uses a learning value obtained by summing the learning values retrieved from the respective maps of the air-fuel ratio learning value storage means. An air-fuel ratio control device for an internal combustion engine with an evaporative fuel control device, wherein the air-fuel ratio control device has a function of setting an air-fuel ratio control amount. 3. A fuel tank for temporarily storing fuel vapor in a fuel tank,
Operating state detecting means for detecting the engine operating state; an operating state detecting means for detecting the engine operating state; and an operating state detecting means for supplying the stored evaporative fuel to the engine intake system while controlling the amount of suction under predetermined engine operating conditions. Air-fuel ratio detecting means for detecting the air-fuel ratio of the air-fuel mixture, air-fuel ratio basic control value setting means for setting a basic air-fuel ratio control value based on the detected engine operating state, and a target air-fuel ratio Air-fuel ratio feedback correction value setting means for setting an air-fuel ratio feedback correction value for increasing / decreasing the control value of the air-fuel ratio so as to approach the learning value, and a learning value for correcting the basic control value of the air-fuel ratio for each operation region. And an air-fuel ratio learning value storage means for storing an average value of the air-fuel ratio feedback correction value at the time of convergence with a reference value for each of the operation regions, and decreasing the air-fuel ratio in a direction to reduce a deviation between the average value and the reference value. Burning Air-fuel ratio learning value updating means for correcting and updating the learning value of the corresponding operation area stored in the learning value storage means, and correcting the basic control value of the set air-fuel ratio with the learning value of the corresponding engine operation area. An air-fuel ratio control value setting unit that corrects the air-fuel ratio with the air-fuel ratio feedback correction value to set a final air-fuel ratio control value. The learning value updating means has a function of correcting and updating the learning value using a correction rate variably set in accordance with the presence or absence of the suction of the evaporated fuel or the ratio of the suction amount. An air-fuel ratio control device for an internal combustion engine.