JPH11270395A - Fuel injection quantity control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify the fuel injection control by detecting quantity of the deposit existing near a throttle valve, correcting open degree of the throttle valve on the basis of the detected variable, and deciding the fuel injection quantity on the basis of the corrected open degree and the engine speed. SOLUTION: A real throttle open degree is detected independently of existence of the deposit (S1). Adhesion quantity of the deposit near a throttle valve as a basic quantity is computed (S2). Deposit correction open degree as an open degree correction value in the case where the deposit is adhered is computed on the basis of the computed adhesion quantity. Throttle open degree for computing the basic injection time is computed on the basis of the throttle open degree, the computed deposit correction open degree and the full closing reference open degree as an open degree at the time of full closing the throttle valve is computed (S3). Finally, basic injection time is computed for decision on the basis of the computed throttle open degree and the engine speed at this stage (S4).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling a fuel injection amount which is mainly applied to an internal combustion engine for an automobile and determines a fuel injection amount based on an opening degree of a throttle valve and a rotation speed of the internal combustion engine. The present invention relates to a fuel injection amount control method for correcting a fuel injection amount by correcting an opening degree of a throttle valve when deposits exist near the valve.

[0002]

2. Description of the Related Art It has been known that deposits composed of lubricating oil components and carbon fine particles derived from combustion products are deposited or adhered to the inner wall of an intake pipe near a throttle valve. In order to eliminate the influence of the deposit on the fuel injection amount, for example, Japanese Patent Application Laid-Open No.
As disclosed in Japanese Patent Application Laid-Open No. 1-129435, the amount of the deposit is detected, a correction amount of the fuel injection amount is calculated according to the detected amount of the deposit, and the fuel injection amount is corrected by the correction amount at the time of starting. What determines is known. In this apparatus, the situation where the injected fuel is adsorbed on the deposit and the required fuel quantity cannot be obtained as a result is improved by modifying the fuel injection quantity according to the deposit quantity.

[0003]

On the other hand, in recent years, an internal combustion system employing a so-called α-N system for determining a fuel injection amount based on an opening of a throttle valve, that is, a throttle opening and an engine speed, has been adopted. Institutions are known. In this method, since the intake air amount is estimated based on the throttle opening, if the detection accuracy of the throttle opening decreases, the fuel injection amount may deviate from the required amount, and the air-fuel ratio may be lean or lean.

[0004] In such an internal combustion engine, if a deposit adheres to the vicinity of the throttle valve, the passage area of the intake pipe decreases even though the throttle valve is open due to the adhesion of the deposit, and the amount of intake air increases. Decrease. However, since the throttle opening is detected in the same way as when there is no deposit, the fuel injection amount is determined based on the throttle opening at that time even though the intake air amount is actually decreasing due to the deposit. Then
The fuel injection amount became excessive, and the air-fuel ratio shifted to the rich side.

[0005] Such a problem is remarkable when the throttle opening is small, and has almost no effect when the throttle valve is opened to a certain degree or more. That is, in the low opening region, the gap between the throttle valve and the intake pipe, which is closed by the deposit, is involved at a high rate with respect to the detected throttle opening, and the influence increases. . For this reason, when deposits are deposited near the throttle valve due to aging or the like, the air-fuel ratio becomes over-rich in a low opening state and drivability is reduced. In order to prevent such a situation, it is conceivable to correct the fuel injection amount with the amount of deposit attached as in the above-mentioned publication, but since the calculation of the fuel injection amount changes depending on the presence or absence of the deposit, the control method Became complicated.

An object of the present invention is to solve such a problem.

[0007]

According to the present invention, the following measures are taken in order to achieve the above object. That is, the fuel injection amount control method according to the present invention detects the amount of deposits present near the throttle valve, corrects the opening of the throttle valve based on the detected amount,
The fuel injection amount is determined based on the corrected opening and the rotation speed.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention relates to a fuel injection amount control method for detecting an opening of a throttle valve of an internal combustion engine and determining a fuel injection amount based on the detected opening and a rotational speed. Detecting the amount of deposits, correcting the detected opening based on the detected amount of deposits, and determining the fuel injection amount based on the corrected opening and the rotation speed. It is a quantity control method.

With such a configuration, when the deposit accumulates in the vicinity of the throttle valve and has an intake air amount corresponding to the opening substantially smaller than the detected opening, the accumulation is performed. Since the detected opening is corrected based on the amount of the object, the opening of the throttle valve when determining the fuel injection amount can be approximated to the actual open state. Therefore, when determining the fuel injection amount, it is possible to always determine the fuel injection amount based on the opening degree and the rotation speed of the throttle valve regardless of the presence or absence of deposits, thereby simplifying the fuel injection control. Can be Further, it is possible to solve the problem that the determined fuel injection amount becomes excessive with respect to the actual intake air amount and the air-fuel ratio becomes over-rich. Therefore, good drivability can be maintained, and in particular, it is possible to prevent the rotation of the internal combustion engine from becoming unstable particularly in a low opening state where the opening of the throttle valve is low.

[0010]

An embodiment of the present invention will be described below with reference to the drawings. An engine 100 schematically shown in FIG. 1 is for an automobile, and its intake system 1 is provided with a throttle valve 2 that opens and closes in response to an accelerator pedal (not shown), and a surge tank 3 on the downstream side thereof. Is provided.
The engine 100 does not adjust the intake air amount for idle rotation control by adjusting the air flow rate of a bypass passage that bypasses the throttle valve 2.
This is a type to which a so-called throttle valve direct-acting idle rotation control system for directly adjusting the intake air amount by directly opening and closing the throttle valve 2 itself during idling operation is applied.

As shown in FIG. 2, the throttle body 110 having the throttle valve 2 therein includes a rotary shaft 113 for supporting the throttle valve 2, a throttle link 114 fixed to the rotary shaft 113, and a lever. 115 and an electric ISC that pushes the lever 115
The actuator includes an actuator 116 and a throttle sensor 16 connected to the rotating shaft 113 to output an electric signal corresponding to the opening of the throttle valve 2, that is, the throttle opening. The rotation shaft 113 is urged in a rotation direction in which the throttle valve 2 closes. The throttle link 114 has
An accelerator wire 114a is connected, and when the accelerator pedal is pressed, the accelerator wire 114a is
Is pulled, the rotation shaft 113 rotates against the urging force, and the throttle valve 2 is opened.

The ISC actuator 116 is a motor 1
16A and a gear device 116b, and the rotation of the motor 116a causes the rod 116c to advance and retreat via the gear device 116b. When the motor 116a stops, the rod 116c is held at that position by the gear device 116b. It is. An idle switch 116d that is turned on when pressed by the lever 115 is integrally attached to the tip of the rod 116c.
Usually, when the accelerator pedal is not depressed, the throttle valve 2 is closed with a predetermined gap formed between the throttle valve 110 and the inner wall of the throttle body 110, and the lever 1
15 comes into contact with the tip of the rod 116c. In this case, the rod 116c is held except for the pull-in position up to the most retracted position, and the throttle valve 2 is stopped at the substantial control start position.

The throttle valve 2 itself can move in a direction to close further from the control start position.
In addition to the SC actuator 116, a stopper (not shown) for mechanically stopping the movement in the closing direction is provided on the outer wall of the throttle body 110. This stopper stops the throttle valve 2 in the fully closed state, that is, ISC
Shortly before the limit of the operation range of the actuator 116, the idle switch 116d is turned off. When the rod 116c is further retracted from this position, the ISC actuator 116 reaches the limit of the operating range.

In the vicinity of one end of the intake manifold 4 of the intake system 1 which communicates with the surge tank 3, a fuel injection valve 5 is further provided.
Is controlled by The exhaust system 20 includes
O ₂ sensor 21 for measuring oxygen concentration in exhaust gas
Is mounted at a position upstream of a three-way catalyst 22 provided in a pipe leading to a muffler (not shown). This O
_{The two} sensors 21 output a voltage signal h corresponding to the oxygen concentration.

The electronic control unit 6 includes a central processing unit 7
And a backup R that stores the fully closed reference opening TAMIN.
And an EEPROM (electrically writable and erasable PRO) storing the AM and the initial idle opening TAIDLINI.
M), an input interface 9,
It mainly comprises a microcomputer system having an output interface 11. The input interface 9 includes an engine speed NE, cylinder discrimination,
And a rotation speed signal Ne, a cylinder discrimination signal G1, and a crank angle reference position signal G2 output from a cam position sensor 14 for detecting a crank angle reference position, and a vehicle speed output from a vehicle speed sensor 15 for detecting a vehicle speed. The signal c, the opening degree of the throttle valve 2, that is, the throttle opening signal d output from the throttle sensor 16 for detecting the throttle opening, and the idle switch 116d output for detecting the closed state of the throttle valve 2 are output. An IDL signal k, a water temperature signal e output from a water temperature sensor 17 for detecting a cooling water temperature of the engine 100,
The voltage signal h output from the O ₂ sensor 21 and the off signal x indicating that the ignition switch IGSW is turned off are input. On the other hand, from the output interface 11, the fuel injection signal f,
An ignition pulse g for the spark plug 18;
A drive signal p for driving the motor 116a of the ISC actuator 116 is output.

The electronic control unit 6 basically outputs the throttle opening TAa based on the throttle opening signal d output from the throttle sensor 16 and the output from the cam position sensor 14 when the deposit is not attached. The basic injection time TP, that is, the basic fuel injection amount is determined using the engine speed NE based on the engine speed signal Ne as the main information. Further, the electronic control unit 6 detects this basic fuel injection amount by detecting the amount of deposits in the vicinity of the throttle valve 2 and correcting the detected opening degree based on the detected deposit amount.
It is programmed to determine based on the corrected opening and the engine speed NE.

In the steady state, the A / F feedback correction coefficient FA set based on the voltage signal h from the O ₂ sensor 21 in order to execute the feedback control.
F, the effective injection time TAU is determined by correcting the basic injection time TP with the learning value KG and other correction coefficients,
The fuel of the injection amount based on the determined effective injection time TAU,
A program for injecting in synchronization with the engine rotation is stored in the electronic control unit 6.

In determining the basic injection time TP, the throttle opening signal d is converted from analog to digital (A / D conversion) as shown in equation (1) in consideration of the adhesion of deposits as deposits. From the A / D input opening VTHAD, which is the current throttle opening TAa detected as a result, the total closing reference opening TAMIN, which is the opening when the throttle valve 2 is fully closed, and the detected deposit amount DEPO are set. The total value obtained by adding the deposit correction opening degree FDEPO is subtracted, and the result is adopted as the substantial, that is, corrected throttle opening degree TA at that time. Fully closed reference opening TA
MIN sets the idle switch 116d at the factory shipment stage.
The adaptation value is stored in the storage device 8 based on the throttle opening degree TAa in a state where is turned on. TA = VTHAD- (TAMIN + FDEPO) (1)

FIG. 3 shows an outline of a program for determining the basic fuel injection amount. First, in step S1, the throttle opening TAa at this time is converted from a throttle opening signal d to analog / digital (A / D conversion) to detect an A / D input opening VTHAD. The A / D input opening VTHAD indicates the actual throttle opening TAa at that time detected regardless of the presence or absence of the deposit. In step S2, the amount of deposit DE which is the basis of the deposit near the throttle valve 2 is determined.
Calculate PO. The adhesion amount DEPO is represented by a numerical value converted into an opening, and is calculated by subtracting an initial idle opening TAIDLINI which is an initial idle opening of the vehicle from a current idle opening TAIDLF during idling operation, as described later. It is. Then, when the attached amount DEPO is calculated, based on the calculated attached amount DEPO,
A deposit correction opening FDEPO, which is an opening correction value when a deposit is attached, is calculated.

Next, in step S3, a throttle for calculating the basic injection time TP by equation (1) from the A / D input opening VTHAD, the calculated deposit correction opening FDEPO and the fully closed reference opening TAMIN. The opening degree TA is calculated. In step S4, the calculated throttle opening TA
And the basic injection time TP is calculated and determined using the engine speed NE at this time.

As described above, the detected actual throttle opening VTHAD is converted into a deposit correction opening FDEPO corresponding to the amount of the deposit for correcting the throttle opening.
The characteristic of the throttle opening TA after correction can be made to substantially match the characteristic of the actual throttle opening TAa when no deposit is attached over the entire effective operating region of the throttle valve 2 by the correction. . That is, the correction of the throttle opening is equivalent to adjusting the difference between the actual opening of the throttle valve 2 and the throttle opening signal d of the throttle sensor 16, that is, the offset amount, in accordance with the deposit correction opening FDEPO. Things.

Accordingly, the corrected throttle opening TA
As shown by the solid line in FIG. 4, the intake air amount characteristic C1 substantially corresponds to the characteristic C2 (shown by an imaginary line) in the case where no deposit is attached, which is moved in parallel to the opening degree. Becomes Therefore, in the low opening range where the opening of the throttle valve 2 is small, the characteristic C1 is the characteristic C1.
2, the intake air amount can be corrected to be substantially the same as when no deposit is attached. As a result, since the calculated basic injection time TP is calculated based on the corrected throttle opening TA, as shown in FIG. 5, the calculated basic injection time TP does not become excessive with respect to the actual intake air amount which decreases due to the adhesion of the deposit. In addition, it is possible to reliably prevent the air-fuel ratio from becoming over-rich. Therefore, an appropriate air-fuel ratio can be maintained even if the deposit is attached,
Drivability does not decrease. A / D
Since the basic injection amount TP is calculated by correcting the input opening degree VTHAD, it is not necessary to change the program for calculating the basic injection amount TP to that at the time of deposit attachment, thereby suppressing an increase in manufacturing cost.

In the above, the deposit amount DEPO
Is calculated based on the throttle opening TAa, i.e., the idle opening during stable idling operation after the warm-up operation is completely completed, which is not a specific operation state such as when the engine 100 is started or during warm-up. This utilizes the fact that the amount of intake air required in the idling operation state after the complete warm-up is substantially constant regardless of the presence or absence of deposits.

The current idle opening TAIDLF and the initial idle opening TAIDLINI for calculating the deposit amount DEPO are determined by the ISC of the feedback correction value DFB in the idle rotation control during idling operation.
It is set based on the learning value DLRN. That is, during idling operation, the required amount of intake air DISC is set from various correction values based on the operating state of the engine 100 at that time. In a state where the complete warm-up is completed, the water temperature correction value DAAV and the starting correction value DST
A, the load correction value DSET, the expected load value DSKP, and the feedback correction value DFB are added to calculate. DISC = DAAV + DSTA + DSET + DSKP + DFB (2)

In this case, for example, when an electric load such as a headlight occurs, the amount of intake air to be increased for that purpose is increased and corrected by the load correction value DSET. Idle opening T
As shown in FIG. 6, Aa fluctuates with time, but the fluctuation of the ISC learning value DLRN is small, and the fluctuation of the idle opening detection value based on this is also small. Further, when the air conditioner operates, the required air amount DISC is corrected by the correction value for that, and the ISC learning value DLRN is fixed instead, so that the idle opening detection value is not affected.

The ISC learning value DLRN is a value excluding a predictable load factor, and reflects a deviation from the control center when performing feedback control. Therefore, by monitoring the ISC learning value DLRN, the idle opening can be detected without using the throttle opening signal d. And the ISC learning value DL
The RN is further smoothed so that a sudden change in the ISC learning value DLRN does not affect the detection of the idle opening, and the ISC learning value DLRN after the smoothing is performed.
That is, the current idle opening TAIDLF and the initial idle opening TAIDLIN are set from the opening smoothing processing value TAIDLN (the change over time is shown in FIG. 7).

FIG. 8 shows an outline of the current idle opening degree TAIDLF detection program. First, in step S11, the ISC learning value DLRN at this time is
Is read, and the idle opening detection value CDLRN is converted based on the ISC learning value DLRN. ISC learning value D
The learning of the LRN includes, for example, driving that satisfies conditions such as that the warm-up operation has been completed after the start, that the vehicle speed is equal to or lower than the set vehicle speed, and that the state in which the electric load or the like has not changed has continued for a predetermined time. If a predetermined condition is satisfied while the feedback control is being performed when the state is reached, the feedback control is performed. In step S12, the idle opening detection value CDLRN converted in step S11 is smoothed to calculate a current opening smoothing value TAIDLN. The smoothing process is calculated by the following equation. TAIDLN _n = TAIDLN _n-1 + (CDLRN _n − TAILDN _n-1 ) / 32 (3)

The calculated opening smoothing processing value TAIDLN
In order to calculate the attached amount DEPO, the latest value, that is, the value when the ignition switch IGSW is off is stored in the storage device 8. Next, in step S13, it is determined whether or not the ignition switch IGSW has been turned off. In this configuration, the power of the electronic control unit 6 is not turned off when the ignition switch IGSW is turned off, but the power is turned off after a predetermined time from the determination of the ignition switch IGSW being turned off. During this predetermined time, the opening degree smoothing value TAIDLN is smoothed. That is, in step S14, the current idle opening TAIDLF is changed to the opening smoothing processing value TAIDL.
N is calculated by a smoothing process using the following equation. This smoothing process is performed by, for example, a change in the atmospheric pressure caused by a difference in altitude of a traveling place or the like.
This is for suppressing the fluctuation of N. TAIDLF _n = TAIDLF _n-1 + (TAIDLN _n − TAILDF _n-1 ) / 32 (4)

The most recently detected, that is, the current idle opening TAIDL immediately before the ignition switch IGSW is turned off.
F is stored in the storage device 8 in the same manner as the opening smoothing processing value TAIDLN. In such a configuration, the current idle opening TAIDLF is determined by the ignition switch IGSW
Is detected each time is turned off. That is, during the idling operation until the ignition switch IGSW is turned off, the control is performed in steps S11 → S12 → S13.
Is repeatedly executed. In this way, by forming the ICS learning value DLRN, I
It is possible to suppress the influence of the fluctuation at the time of detection of the SC learning value DLRN on the opening smoothing processing value TAIDLN (shown in FIG. 9).

Further, when the operation of the engine 100 is terminated and the ignition switch IGSW is turned off, control is performed in steps S11 to S14 within a delay time until the power supply to the electronic control unit 6 is cut off. By executing, the current idle opening TAIDLF is detected. Since the current idle opening TAIDLF is detected by averaging the latest opening smoothing processing value TAIDLN calculated immediately before the ignition switch IGSW is turned off, a change in the environment including a change in the atmospheric pressure, that is, the opening over a long period of time. The current idle opening degree TAIDLF can be detected while suppressing the influence of the fluctuation of the annealing value TAIDLN.

On the other hand, the initial idle opening TAIDL
INI is the current idle opening degree TAIDLF when the fluctuation amount of the current idle opening degree TAIDLF satisfies a predetermined condition.
Is determined to be stable and detected. That is,
The current idle opening TAIDLF is, as shown in FIG.
At the time of an initial running-in operation such as a mechanical loss of the engine 100, the opening degree decreases with the passage of time, and after a certain running-in operation is completed, almost no change continues. is there. Thereafter, the throttle opening degree TAa increases with time due to the adhesion of the deposit.

FIG. 11 shows an outline of the initial idle opening degree TAIDLINI detection program. First, in step S21, the initial idle opening degree TAI
It is determined whether or not DLINI has been updated. Step S2
In step 2, it is determined whether or not the absolute value obtained by subtracting the current idle opening TAIDLF _n-1 detected last time from the current idle opening TAIDLF _n detected this time is less than a predetermined value δ. In step S23, steps S21 and S22
It is determined whether or not the number of times that is satisfied is equal to or greater than a predetermined number K. In steps S21, S22, and S23, it is determined whether the current idle opening TAIDLF is stable. In step S24, the current idle opening TAIDLF detected at this time is replaced with the initial idle opening TAIDLIN.
Set as I.

In such a configuration, the engine 100
The current idle opening TAI
Since the DLF decreases with the passage of time, the initial idle opening degree TAIDLINI varies greatly, and the absolute value of the variation does not become smaller than the predetermined value δ. Therefore, the control proceeds from step S21 to step S22, and the initial idle opening TAIDLINI is not set. When the running-in operation is completed and the current idle opening TAIDLF is stabilized and the absolute value of the variation is smaller than the predetermined value δ, the control proceeds to steps S21 → S22 → S23, and the absolute value of the variation is further determined. Is detected a predetermined value δ a predetermined number K or more, the control executes steps S21 to S24 to set the current idle opening TAIDLF at that time to the initial idle opening TAIDLINI. As a result, the initial idle opening TAIDLINI is detected, and the result is written into the EEPROM of the storage device 8.

On the other hand, as described above, once the initial idle opening TAIDLIN is detected, it is determined in step S21 that the initial idle opening TAIDLIN is to be updated. Even if the initial idle opening TAI
DINI is not updated. Therefore, the initial idle opening TAIDLIN is normally detected only once after the engine 100 is operated after manufacturing.

Therefore, even if the relationship between the throttle opening signal d output from the throttle sensor 16 and the throttle opening for each engine varies, the current idle opening at that time when a predetermined condition is satisfied. TAIDLF
Is set as the initial idle opening degree TAIDLINI, so that the detection accuracy can be increased. As a result, the calculation of the deposit amount DEPO, which will be described later, can be performed accurately, and the deposit attachment is not erroneously detected.

The outline of the deposit detection program is as shown in FIG. 12 and FIG. First, a basic program for detecting the deposit amount DEPO will be described. In step S31, the current idle opening TAIDLF at this time is read. In step S32, the initial idle opening degree TAIDNINI is read. In step S33, the initial idle opening degree TAIDLINI is subtracted from the current idle opening degree TAIDLF, and the adhesion amount DEP is calculated.
O is calculated and detected.

As described above, the above-described ISC learning value DLR
N from the current idle opening TAIDLF and the initial idle opening TAIDLIN detected based on N.
Does not require a special sensor. Therefore, the attached amount DEPO can be detected in the existing engine 100, and in the case of the new engine 100, an increase in the number of components can be suppressed, and an increase in manufacturing cost can be suppressed.

The deposit correction opening FDEPO is calculated based on the amount of adhesion DEPO thus detected.
The outline of the deposit correction opening FDEPO calculation program is as shown in FIG. First, step S
At 41, it is determined whether or not the vehicle is idling. The determination during idling operation is performed, for example, using the throttle valve 2
Is in a fully closed state, the vehicle speed is equal to or lower than a predetermined speed, and the fuel cut during deceleration is not performed. In step S42, the engine 10
When the temperature of 0, for example, the cooling water temperature is equal to or higher than a predetermined temperature, it is determined whether or not the engine 100 is completely warmed up. In step S43, the attached amount DEPO is changed from the current idle opening TAIDLF to the initial idle opening TAIDL.
INI is subtracted, and the calculated adhesion amount DEPO is a predetermined value α for the previously detected deposit correction opening FDEPO _n-1.
It is determined whether the value is larger than the value obtained by adding. this is,
In order to take into account changes in the throttle opening TAa during idling operation, the amount of deposit DEPO that is expected to decrease drivability is determined. According to this determination, even when the deposit is attached, the attached amount DEPO which does not affect the drivability is determined.
The correction of the throttle opening TAa due to the adhesion of the deposit is not performed.

In step S44, it is determined whether the A / F feedback correction coefficient FAF to which the feedback learning value KG has been added is smaller than a predetermined value β. This determination prevents erroneous detection of deposit adhesion. In other words, even if the throttle opening TAa is the same, if the deposit is attached, the air-fuel ratio is low, that is, rich, because the intake air amount decreases.
Accordingly, the A / F feedback correction value FAF is corrected so that the air-fuel ratio becomes higher. If the result is smaller than the predetermined value β, it is determined that the air-fuel ratio is lower due to adhesion of the deposit. Things. On the other hand, when the air-fuel ratio is high even though the throttle opening TAa is appropriate, the A / F feedback correction value FAF is controlled to be large. There is no judgment. In step S45, the current deposit correction opening FDEPO _n is added to the previous deposit correction opening FDEPO by the deposit correction amount DEPO.
Set to the value obtained by adding PO _n-1 .

In such a configuration, if the deposit is not attached, or if the attached amount is small enough not to affect drivability, if the idling operation state after the completion of warm-up, the control is performed as follows. Step S41
The process proceeds from S42 to S43, and this control ends. Also,
Although the deposit amount DEPO affects the drivability, the A / F feedback correction value F
If the value obtained by adding the feedback learning value to the AF is equal to or larger than the predetermined value β (step S44), the control ends because the air-fuel ratio has not changed to the rich side.

On the other hand, the amount of adhesion DEPO is more than a predetermined amount, that is, the opening degree of the throttle valve 2 is changing in the opening direction, and the A / F feedback correction amount FAF and the feedback learning value are changed. When the total value of KG is less than the predetermined value β and the air-fuel ratio is changing to the rich side, the control is performed in steps S1 → S42 →
Proceeding from S43 to S44, it is detected that the deposit is attached in an amount that requires the opening degree correction. Thereafter, step S45 is executed to execute the current deposit correction opening degree FDEP.
To calculate the O _n. Then, the throttle opening TA is calculated by applying the current deposit correction opening FDEPO _n to the above equation (1).

As described above, the adhesion of the deposit is determined by the amount of adhesion DEPO, in other words, the change in the idle opening and the A / F
Since the detection is performed based on the change in the feedback correction coefficient FAF, that is, the air-fuel ratio, it is not necessary to prepare a special sensor for deposit detection, and it is possible to suppress an increase in the number of parts.
An increase in manufacturing cost can be suppressed. Further, by monitoring the deviation of the air-fuel ratio, it is possible to prevent erroneous detection of deposit adhesion.

The present invention is not limited to the embodiment described above. In addition, the configuration of each unit is not limited to the illustrated example, and various modifications can be made without departing from the spirit of the present invention.

[0044]

As described above, according to the present invention, when the deposit is deposited near the throttle valve and the amount of intake air corresponds to the opening substantially smaller than the detected opening. However, since the detected opening is corrected based on the amount of the deposit, the opening of the throttle valve when determining the fuel injection amount can be approximated to the actual open state. For this reason, when determining the fuel injection amount, the fuel injection amount can always be determined based on the opening degree and the rotation speed of the throttle valve regardless of the presence or absence of deposits, and the fuel injection control is simplified. be able to. Therefore, it is possible to solve the problem that the determined fuel injection amount becomes excessive with respect to the actual intake air amount and the air-fuel ratio becomes over-rich. As a result, good drivability can be maintained, and in particular, it is possible to prevent unstable rotation of the internal combustion engine in a low opening state where the opening of the throttle valve is low.

[Brief description of the drawings]

FIG. 1 is a schematic configuration explanatory view showing one embodiment of the present invention.

FIG. 2 is a schematic configuration explanatory view schematically showing the configuration of the throttle body of the embodiment.

FIG. 3 is a flowchart showing a control procedure of throttle opening correction of the embodiment.

FIG. 4 is an operation explanatory view of the embodiment.

FIG. 5 is an operation explanatory view of the embodiment.

FIG. 6 is an operation explanatory diagram for explaining the principle of idle opening detection of the embodiment.

FIG. 7 is an operation explanatory diagram for explaining the principle of idle opening detection of the embodiment.

FIG. 8 is a flowchart illustrating a control procedure of idle opening detection according to the embodiment.

FIG. 9 is an operation explanatory diagram for explaining the principle of idle opening detection of the embodiment.

FIG. 10 is an operation explanatory diagram for explaining the principle of idle opening detection of the embodiment.

FIG. 11 is a flowchart showing a control procedure for detecting an initial idle opening in the embodiment.

FIG. 12 is a flowchart showing a control procedure for detecting the amount of deposit on the deposit according to the embodiment.

FIG. 13 is a flowchart illustrating a control procedure of a deposit correction opening calculation according to the embodiment.

[Explanation of symbols]

 2 ... Throttle valve 6 ... Electronic control device 7 ... Central processing unit 8 ... Storage device 9 ... Input interface 11 ... Output interface

Claims (1)

[Claims] 1. A fuel injection amount control method for detecting an opening degree of a throttle valve of an internal combustion engine and determining a fuel injection amount based on the detected opening degree and a rotation speed. A fuel injection amount control method, comprising: detecting and correcting a detected opening degree based on a detected amount of deposits; and determining a fuel injection amount based on the corrected opening degree and rotation speed.