JPH02215940A - Fuel supply controller for internal combustion engine - Google Patents

Abstract

PURPOSE:To secure an operational chance of transient compensation value even at time of engine low speed as well as to avoid any lean misfire at the initial stage of acceleration by converting the time unit transient compensation value per constant time of a heat engine load parameter into the compensation value per constant crank angle on the basis of engine speed, and setting the final transient compensation value. CONSTITUTION:A time unit compensation value operational means operates a time unit transient compensation value on the basis of a variation in an engine load parameter per constant time. In brief, this time unit transient compensation value is of transient compensation value corresponding to a constant time operated on the basis of a variation in the engine load parameter per constant time. This transient compensation value operational means converts the time unit compensation value set in response to the constant time into the transient compensation value per constant crank angle on the basis of engine speed, and operates the final transient compensation value as a transient compensation value equivalent to the constant crank angle. On the basis of this transient compensation value, a transient compensation control means controls a fuel supply for compensation.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a fuel supply control device for an internal combustion engine, and more particularly to correction control of a fuel supply amount during transient engine operation.

<Prior Art> The following types of fuel supply control devices for internal combustion engines are known. The intake air flow rate Q and intake pressure PB are detected as state quantities related to the intake air, and the basic fuel supply amount Tp is calculated based on these and the detected value of the engine rotation speed N. Then, the basic fuel supply amount Tp is adjusted to various correction coefficients C0EF1 based on operating conditions such as engine temperature.
．． Feedback correction coefficient LAMBDA set based on the air-fuel ratio obtained through detection of oxygen concentration in exhaust gas
.

Calculate the final fuel supply 1iTi by correcting it with the correction numerator s etc. based on the battery voltage Ti-'rpxCOEF
XLAMBDA+Ts), and the calculated amount of fuel is supplied to the engine by a fuel injection valve or the like.

However, the fuel supply amount Ti corresponds to the engine demand during steady operation, and for example, during acceleration, the air-fuel ratio becomes lean due to a delay in the transport of liquid fuel (wall flow) that adheres to the inner wall of the intake passage. There was a problem that the engine output did not respond well and the acceleration performance worsened.

Therefore, as mentioned above, the basic fuel supply amount Tp is calculated based on the intake air flow rate Q and the intake pressure PB, or the basic fuel supply amount Tp is calculated from the throttle valve opening TVO and the engine rotation speed N. Calculate the amount of change in (fuel supply interval) and use this amount of change as the basic correction amount, and use this basic correction amount as, for example, the cooling water temperature Tw, the basic fuel supply amount Tp5 at the beginning of transient operation, the engine rotation speed N, etc. A configuration has previously been proposed in which a final wall flow correction amount (transient correction amount) is set by correcting based on the wall flow correction amount, and the fuel supply amount is corrected using this wall flow correction amount (Japanese Patent Application No. 1982- 2819
No. 63, Japanese Patent Application No. 63-39711, etc.).

In addition, when setting the wall flow correction amount as described above, the previous time (
A value obtained by attenuating the wall flow correction amount set before a certain crank angle) with a predetermined damping characteristic value is compared with the latest wall flow correction amount based on the basic correction amount, and the larger one is selected. That's how it is.

Here, the process of deriving the calculation formula for the wall flow correction amount based on the amount of change in the basic fuel supply amount Tp between constant crank angles as described above will be explained.

The amount of fuel Qin actually supplied into the cylinder can be determined, for example, from the following theoretical formula, taking into account the wall flow.

Here, Qau t is the amount of fuel supplied by the fuel injection valve, and Qau t is the evaporation rate. Therefore, in the above theoretical formula, QoutXα- of the fuel supplied by the fuel injection valve becomes a wall flow and adheres, so this amount is subtracted. The amount of fuel Qin actually supplied into the cylinder is determined by adding the evaporated amount assuming that only a predetermined proportion of the amount is evaporated and supplied into the cylinder.

Furthermore, the wall flow correction scale in steady state may be set so that the adhering portion of the supplied fuel and the evaporated portion of the wall flow are balanced, so it is sufficient to satisfy the following equation.

D + crg (ΣQw 10 (Qou 10) αw )
−(Qout 10) αw= 0 Therefore, the wall flow correction amount is also: Wall flow correction amount (transient correction amount) D during load fluctuation
φ is the adhesion rate and evaporation rate in the previous time, α-1, αg-
1, then Substituting this into the equation for the wall flow correction scale above, αg-αg-' (see Figure 7), we get:
Qout-' is the amount of fuel supplied by the previous fuel injection valve.

Therefore, the calculation formula for the wall flow correction amount Dφ is based on the basic fuel supply amount T in the previous injection (injection before a certain crank angle).
If P is Tp-1, D φ =K (Tp-Tp
- turbidity). However, K
=f (Q/NorPB).

According to the proximal equation for the wall flow correction amount Dφ derived in this way, the wall flow correction amount (transient correction amount) was set as described above. The calculation load on the unit is reduced.

<Problems to be Solved by the Invention> By the way, in setting the wall flow correction amount based on the amount of change in the basic fuel supply amount Tp as described above, it is necessary to calculate the amount of change in the fuel actually supplied from the fuel injection valve. Conventionally, as mentioned above, it is necessary to calculate the
The amount of change in the basic fuel supply amount Tp is determined for each degree (°), and the wall flow correction amount is set from this amount of change.

However, when the engine is at low rotation speed, the time required to rotate by the constant crank angle becomes longer, so as shown in FIG. , wall flow correction amount KF
There is a problem in that the addition of the UEL may be delayed, making it impossible to prevent lean misfires at the beginning of acceleration.

The present invention has been made in view of the above-mentioned problems, and aims to prevent malfunctions such as lean misfires at the beginning of acceleration by adding a wall flow correction amount with good response even when the engine rotates at low speeds. The purpose is to

<Means for Solving the Problems> Therefore, in the present invention, as shown in FIG. an engine load parameter calculating means for calculating an engine load parameter at fixed time intervals based on the detected engine operating conditions; and calculating an amount of change in the engine load parameter calculated by the engine load parameter calculating means per the fixed time period. A change calculation means; A time unit correction amount calculation means for calculating a time unit transient correction amount based on the change amount calculated by the change amount calculation means; Transient correction amount calculation means for converting the correction amount into a transient correction amount per constant crank angle based on the engine rotational speed and setting the final transient correction amount, and the transient correction amount calculated by the transient correction amount calculation means. A fuel supply control device for an internal combustion engine is configured to include: transient correction control means for correcting and controlling the fuel supply amount based on;

Further, as shown by the dotted line in FIG. 1, attenuation correction amount calculation means calculates an attenuation correction amount by decreasing the transient correction amount based on a predetermined damping characteristic value at each of the constant crank angles, and this attenuation correction. The attenuation correction amount calculated by the amount calculation means is compared with the latest transient correction amount calculated by the transient correction amount calculation means, and when the attenuation correction amount is larger, the transient correction amount calculated by the transient correction amount calculation means is It is preferable to provide attenuation control means for forcibly setting the attenuation correction amount to the final transient correction amount instead of the correction amount.

In this configuration, the engine operating condition detection means detects the engine operating conditions related to the intake air amount of the engine, and the engine load parameter calculation means calculates the engine load parameters at regular intervals based on the engine operating conditions. Calculate.

The change amount calculation means calculates the amount of change in the engine load parameter per certain period of time during which the engine load parameter is calculated, and the hourly correction amount calculation means calculates the time unit transient correction amount based on this change amount. That is, the time unit transient correction amount is a transient correction amount corresponding to the certain period of time that is calculated based on the amount of change in the engine load parameter per certain period of time.

Then, the transient correction amount calculation means converts the time unit transient correction amount set corresponding to a certain time as described above into a transient correction amount per constant crank angle based on the engine rotation speed, A final transient correction amount is calculated as a transient correction amount corresponding to a constant crank angle.

The transient correction control means corrects and controls the fuel supply amount based on the transient correction amount calculated in this manner.

On the other hand, the attenuation correction amount calculation means calculates an attenuation correction amount by decreasing the transient correction amount based on a predetermined damping characteristic value at each of the constant crank angles.

Then, the attenuation control means compares the attenuation correction amount set by decreasing correction at each constant crank angle with the latest transient correction amount, and when the attenuation correction amount is larger,
The attenuation correction amount is forcibly set to the final transient correction amount instead of the calculated transient correction amount.

Therefore, the transient correction amount is attenuated at every constant crank angle, and if the attenuated correction amount is larger than the latest calculated value, the attenuation correction amount is adopted as the transient correction amount. It is.

<Example> The present invention will be explained in detail below.

In FIG. 2 showing the system configuration of one embodiment, an internal combustion engine 1 includes an air cleaner 2. Air is taken in through the intake duct 3, the throttle chamber 4, and the intake manifold 5. The air cleaner 2 is provided with an intake air temperature sensor 6 that detects an intake air temperature (atmospheric temperature) TA.

The throttle chamber 4 is provided with a throttle valve 7 that operates in conjunction with an accelerator pedal (not shown) to control the intake air flow rate Q. The throttle valve 7 includes a potentiometer that detects its opening degree TVO, and an idle switch 8A that is turned on when it is in its fully closed position (idle position).
A throttle sensor 8 including a throttle sensor 8 is attached.

The intake manifold 5 downstream of the throttle valve 7 is provided with an intake pressure sensor 9 for detecting intake pressure (intake negative pressure) PB, and an electromagnetic fuel injection valve 10 is provided for each cylinder. The electromagnetic fuel injection valve 10 is driven to open by a drive pulse signal output from a control unit 11 containing a microcomputer, which will be described later, in synchronization with, for example, ignition timing, and is fed under pressure from a fuel pump (not shown) by a pressure regulator. Fuel controlled to a predetermined pressure is injected and supplied into the intake manifold 5. That is, the amount of fuel supplied by the fuel injection valve 10 is controlled by the valve opening driving time of the fuel injection valve 10.

Further, a water temperature sensor 12 is provided to detect the cooling water temperature Tw in the cooling jacket of the engine l, and the exhaust passage 1
An oxygen sensor 14 is provided within the engine 3 to detect the air-fuel ratio of the intake air-fuel mixture by detecting the oxygen concentration in the exhaust gas.

The control unit 11 counts the crank unit angle signal PO8 outputted from the crank angle sensor 15 in synchronization with the engine rotation for a certain period of time or at every predetermined crank angle position (every 180'' in the case of 4 cylinders, and in this embodiment This constant crank angle position is the fuel injection start timing for each cylinder.)
The engine rotation speed N is detected by measuring the period TREF of EF.

In addition, a transmission attached to the engine 1 is provided with a vehicle speed sensor 16 for detecting vehicle speed and a neutral sensor 17 for detecting a neutral position, and these signals are input to the control unit 11.

Additionally, an auxiliary air passage 18 bypassing the throttle valve 7
is provided with an electromagnetic idle control valve 19 that controls the idle rotation speed via the amount of auxiliary air.

The control unit 11 mainly uses the intake pressure PB detected by the intake pressure sensor 9 as the basic fuel injection amount Tp.
In addition to calculating PB, this basic fuel injection amount 'rpPB
The final fuel injection amount MTi (pulse width of the injection pulse signal) is calculated by adding corrections according to various engine operating conditions to
Fuel injection valve 10 based on set fuel injection 11MTl
Open drive control. Therefore, the engine 1 in this embodiment is equipped with a fuel supply control device using an intake pressure detection method generally called the D-Jetro method.

Further, the control unit 11 feedback-controls the idle rotation speed to the target idle rotation speed by controlling the opening degree of the idle control valve 19 during idle operation detected based on the idle switch 8A and the neutral sensor 17.

Next, various calculation processes for fuel supply control performed by the control unit 11 will be explained according to the routines shown in the flowcharts of FIGS. 3 to 6, respectively.

In this embodiment, the engine load parameter calculation means, the change amount calculation means, and the hourly correction amount calculation means.

The functions of the transient correction amount calculation means, the transient correction control means, the attenuation correction amount calculation means, and the fIIA attenuation control half control means are as follows.
The software is provided as shown in the flowcharts of FIGS. In addition, in this embodiment, in addition to the basic fuel injection amount TpPB based on the intake pressure PB, the basic fuel injection amount αNTp (engine load parameter) calculated based on the throttle valve opening TVO and the engine rotation speed N is used.
The wall flow correction amount (transient correction amount) is calculated by monitoring changes in the throttle sensor 8. The crank angle sensor 15 and the like correspond to engine operating condition detection means.

The routine shown in the flowchart of FIG. 3 is a fuel injection amount MTi calculation routine, which is executed every 10++s.

In step 1 (indicated as Sl in the figure; the same applies hereinafter), the engine rotation is calculated based on the opening degree TVO of the throttle valve 7 detected by the throttle sensor 8 and the periodic time TREF of the reference angle signal REF. Input speed N, etc.

In step 2, the ROM of the microcomputer is stored in advance based on the throttle valve opening degree TVO input in step 1.
Search and find the opening area A of the engine intake system from the map set in .

In setting the opening area A, it is preferable to include the opening area of the auxiliary air passage 18 that is variably controlled by the idle control valve 19.

In the engine 3, based on the value A/N obtained by dividing the opening area A obtained in step 2 above by the engine rotation speed N,
The basic volumetric efficiency QHφ corresponding to the A/N is found by searching from a map set in advance in the ROM.

In step 4, R
Search from the map set in OM. Furthermore, the intake pressure P
B is input from the intake pressure sensor 9 every 4 ms according to the routine shown in the flowchart of FIG.

In step 5, the volumetric efficiency QCYL corresponding to the intake system opening area detection method is calculated according to the following formula, so that the volumetric efficiency QCYL based on the opening area A approximately traces the true engine load.

QCYL-QHφxK2+QCYL (1- to 2) where QHφ is the basic volumetric efficiency searched in step 3 above, K
2 is the primary lag correction coefficient retrieved in step 4, QCYL on the right side is the volumetric efficiency calculated in step 5 when this routine was last executed, and during transient operation when the opening area A changes, the downstream of the throttle valve 7 is Since there is a delay in the change in true volumetric efficiency QCYL due to the manifold volume,
This can be approximately determined by a first-order lag system determined by 2.

In the next step 6, the volumetric efficiency Q calculated in step 5 is
Based on CYL, the basic fuel injection amount (engine load parameter) αNTp corresponding to the opening area A detection method is calculated by the following formula. Note that in the formula below, KCONA is a constant.

αNTp4-KCONAXQCYL N At step 7, the basic fuel injection amount αNTPIIL calculated in step 26 during the previous execution of this routine is calculated from the basic fuel injection amount αNTp calculated in step 6 above.
11 is subtracted to obtain the change amount DcrNTp(l抛S
Calculate the amount of change in winnings).

In step 8, the basic fuel injection amount αNTp calculated in step 6 this time is used as the previous value αN
Set it to T poto.

In step 9, the wall flow correction proximal coefficient K used for calculating the wall flow correction amount PRETp, which will be described later, is calculated based on the cooling water temperature Tw detected by the water temperature sensor 12, the intake pressure PB, or the intake pressure P.
The basic fuel injection amount TpPB based on B and the engine rotational speed N are set by multiplying each other by coefficients found by searching from a map.

In step IO, it is determined whether the change amount DcXNTp of the basic fuel injection amount αNTp calculated in step 7 is positive or negative. Here, the amount of change DcxNTp is a negative value (
When it is determined that DαNTp<O), the engine l is in a deceleration operating state where the basic fuel injection amount αNTp is changing in the decreasing direction. In step 12, the amount of change DaNTp calculated in step 7 is subtracted from zero, so that the amount of change DαNT is calculated as a negative value.
Convert p to a positive value (calculate the absolute value of the change 11DαNTp).

On the other hand, when it is determined in step 10 that the change amount DαNTp is a positive value (DαNTp>O), the engine 1 is in an accelerating operation state in which the basic fuel injection amount αNTp is changing in an increasing direction, and in this case, the step The process advances to step 13 and the flag F is set to 1.

Further, when it is determined in step 10 that the amount of change DαNTp is approximately zero, the engine 1 is in a steady operating state in which the basic fuel injection amount αNTp hardly changes, and in this case, each of steps 11 to 19 described later is performed. Jump to the calculation (calculation of the wall flow correction amount PRETp) and proceed to step 2.
Go to 0.

When the transient operation of the engine 1 is determined in step 10 and flag F is set, the wall flow correction amount PRET corresponding to the load fluctuation state (transient operation state) of the engine 1 is set in step 14.
p is calculated according to the following formula.

PRETp"KXDαNTpXTREF In the above calculation formula, K is the wall flow correction approximation coefficient calculated in step 9, DαNTp is the amount of change per fixed time in the basic fuel injection amount αNTP calculated in step 7, and TREF is the value shown in the sixth diagram described later. The reference angle signal RE set in the routine
This is the periodic time of F.

As mentioned above, the wall flow correction amount during load fluctuation is Kx
Since it is approximated by (Tp-Tp-') (Tp-' is the previous value), in the above calculation formula, the wall flow correction amount (time The unit transient correction amount) corresponds to KXDαNTP, and by multiplying this KXDcrNTp by the period time TREF of the reference angle signal REF, the wall flow correction amount KXDαNTp corresponding to the constant time can be changed to a constant crank angle (corresponding to the actual injection interval). 180@) to approximate the amount required by engine 1.

Therefore, while the wall flow correction amount PRETp is calculated every 10 m5, which is the execution cycle of this routine, in the transient operating state of the engine l, the amount approximately corresponds to the actual fuel injection interval. For example, even when the rotational speed N is low at the beginning of acceleration, calculation is performed every 10 as to ensure a calculation opportunity, so that the addition of the wall flow correction amount PRETp (wall flow correction amount increased during acceleration TpKFLP to be described later) is delayed. This can prevent the air-fuel ratio from becoming lean due to

After calculating the wall flow correction amount PRETp in step 14, the flag F is determined in the next step 15. As mentioned above, the flag F is set to l during acceleration and zero during deceleration. It is.

In the accelerating operating state of the engine 1 where the flag is determined to be 1 in step 15, the process proceeds to step 16, where the acceleration wall flow correction amount (increase correction amount) TpKFLP and the wall flow newly calculated in step 14 are calculated. The correction amount PRETp is compared with the correction amount PRETp, and when PRETP>TpKFLP, the process proceeds to step 17 and the wall flow correction amount PRETp is set to the wall flow correction amount TpKFLP during acceleration. On the other hand, PRETp≦'rp
When it is KF L P, the process jumps to step 17 and proceeds to step 20.

Since the initial value of wall flow correction amount TpKFL, P during acceleration is zero, PRETp is set in TPKFLP at the first time of acceleration detection, but TpKFLP is attenuated for each reference angle signal REF according to the routine shown in Figure 6, which will be described later. Therefore, in the continuous acceleration state, the wall flow correction fl P RE T p calculated every 3 strokes is compared with the wall flow correction amount TpKFLP during acceleration that is attenuated for each reference angle signal REF, and the larger one is The acceleration wall flow correction amount TpKFLP is set.

Similarly, when the engine l is in a decelerating operating state where the flag F is determined to be zero in step 15, the process proceeds to step 18, where the deceleration wall flow correction amount (reduction correction amount) TpKFLM is newly calculated in step 14. Wall flow correction amount PRET
p and if PRETp>TpKFLM, proceed to step 19 and perform wall flow correction 11TpKFL during deceleration.
Set the wall flow correction amount PRETp in M. On the other hand, P.R.E.
When Tp≦TpKFLM, the process jumps to step 19 and proceeds to step 20.

The wall flow correction amount during deceleration TpKFLM is also the wall flow correction amount during acceleration 1]T
Like pKFLP, attenuation is set for each reference angle signal REF according to the routine shown in FIG. Wall flow correction amount TpKFL during deceleration.

M is compared, and the larger one is the wall flow correction MTp during deceleration.
Set to KFLM.

In the next step 20, according to the routine shown in FIG.
Based on the intake pressure PB that is input every -3, the basic volumetric efficiency KPB is retrieved from a map stored in the ROM of the microcomputer in advance.

In step 21, the basic volumetric efficiency KPB retrieved in step 20 is added to the minute correction coefficient KF retrieved based on the intake pressure PB and engine rotational speed N in step 52 of the background job shown in the flowchart of FIG.
The final volumetric efficiency KQCYL is calculated by multiplying by LAT.

Then, in step 22, basic fuel injection ITpPB is calculated based on the intake pressure PB according to the following equation.

TpP13-KCONDXKQCYLXPBXKTA where KCOND is a constant, KQCYL is the volumetric efficiency calculated in step 21, PB is the intake pressure input every 4 ms, and KTA is determined by the intake air temperature sensor 6 in step 51 of the background job shown in the fifth figure. This is an intake air temperature correction coefficient retrieved from a map based on the detected intake air temperature TA.

In the next step 23, the basic fuel injection amount TPPB calculated in step 22 is subjected to various corrections according to the engine operating state according to the following formula to calculate the fuel injection amount Ti.

T 14-2 x'r p PB XLAMBDAX
KBLRRC A feedback correction coefficient, KBLRC, is an air-fuel ratio learning correction coefficient, C0EF, which is set by learning the deviation of the feedback correction coefficient LAMBDA from the reference value.
are various correction coefficients set mainly based on the cooling water temperature Tw detected by the water temperature sensor 12, and Ts is a voltage correction amount for correcting a change in the effective valve opening time of the fuel injection valve IO due to the battery voltage.

Furthermore, in the next step 24, wall flow correction fiTpKFLP during acceleration is added to the fuel injection amount Ti to obtain Tp during acceleration.
In addition to applying an increase correction according to KFLP, the deceleration wall flow correction amount TpKFLM is subtracted to perform a decrease correction according to TpKFL and M during deceleration. Therefore, in this embodiment, the wall flow during acceleration which is a positive value The wall flow correction is performed as the sum of the correction ITpKFLP and the deceleration wall flow correction amount TpKFLM which is a negative value.

Next, the routine shown in the flowchart of FIG. 6 is executed every time the reference angle signal REF is output from the crank angle sensor 15, and an injection pulse signal is output to the fuel injection valve 10 according to this routine.

Attenuation settings for wall flow correction amounts TpKFLP and TpKFLM and calculation of an air-fuel ratio correction coefficient are performed.

First, in step 31, by subtracting the free run counter value FRCOL11 at the time of the previous execution of this routine from the current value of the free run counter FRC, the free run counter FRCOL11 during the output of the reference angle signal REF is subtracted from the current value of the free run counter FRC.
The up value of RC, that is, the output period TREF of the reference angle signal REF is calculated.

In the next step 32, the current value of the free run counter FRC is set to the previous value FRCot for use in the calculation in step 31 the next time this routine is executed.

In step 33, the fuel injector 1 installed in the cylinder whose injection start timing is the current reference angle signal REF.
0, an injection pulse signal having a pulse width equivalent to the latest fuel injection amount MTi set in the flowchart of FIG. 3 is output, and the fuel injection valve 10 is opened for a time corresponding to the fuel injection fiMTi. to inject and supply fuel to engine l. Among the reference angle signals REF output from the crank angle sensor 15, for example, the one corresponding to the injection start timing of the #1 cylinder can be distinguished from the others, so that the reference angle signal REF can be made to correspond to each cylinder. This allows fuel to be injected and supplied to each cylinder at a predetermined timing.

In the next step 34, the acceleration wall flow correction amount TpKFLP
is substantially zero or not, and determines the wall flow correction amount Tp during acceleration.
When KFLP is not approximately zero, the process proceeds to step 35, where TpKFLP is multiplied by the damping characteristic value DECK to obtain TpK.
Set FLP to decrease.

Therefore, until the acceleration wall flow correction amount TpKFLP becomes zero, TpKFLP is adjusted for each reference angle signal REF according to this routine.
KFLP is subjected to attenuation processing, and is calculated every 10 s+s according to the routine shown in the flowchart of FIG.
ETp) and the attenuation correction amount subjected to the attenuation processing here, and the larger one is selected.

In the next step 36, the wall flow correction amount T during deceleration is similarly performed.
It is determined whether pKFLM is approximately zero or not, and if the wall flow correction amount TpKFLM during deceleration is not zero, step 3
Proceeding to step 7, TpKFLM is multiplied by the attenuation characteristic value DECK to set TpKFLM to decrease.

In step 38, the air-fuel ratio feedback correction coefficient L used for calculating the fuel injection amount Ti in step 23 is
AMBDA is calculated as follows, for example. When the oxygen sensor 14 detects that the engine intake air-fuel mixture is rich (lean) with respect to the target air-fuel ratio (stoichiometric air-fuel ratio), the air-fuel ratio feedback correction coefficient LAMBDA is calculated by a predetermined integral. While gradually decreasing (increasing) according to the constant, rich
When the lean state is reversed, a predetermined proportion is added or subtracted, and the air-fuel ratio detected by the oxygen sensor 14 is calculated to approach the target air-fuel ratio.

In the next step 39, an air-fuel ratio learning correction coefficient KBLRC is calculated based on the air-fuel ratio feedback correction coefficient LAMBDA. This air-fuel ratio learning correction coefficient KBL
RC is set so that the air-fuel ratio obtained without the air-fuel ratio feedback correction coefficient LAMBDA becomes the target air-fuel ratio, and the control center value (
The average value of the maximum value and the minimum value) is calculated, and the deviation between this control center value and the reference value corresponds to the correction amount.For example, multiple operations classified by basic fuel injection ITpPB and engine rotation speed N The deviation amount is stored in the map for each state.

In this embodiment, the wall flow correction amount PRETp is calculated by calculating the amount of change in the basic fuel injection amount αNTp calculated based on the opening area A of the intake system and the engine rotational speed N at regular intervals. However, instead of the basic fuel injection amount αNTp as the engine load parameter, the amount of change in the basic fuel injection amount TpPB based on the intake pressure PB may be calculated. In a device equipped with an air flow meter that detects Q, the wall flow correction amount PRETp may be calculated by determining the amount of change in the basic fuel injection amount TpQ based on this intake air flow rate Q in the same manner as in this embodiment. .

<Effects of the Invention> As explained above, according to the present invention, the amount of change in the engine load parameter per fixed time is calculated, and the amount of hourly transient correction is calculated based on this amount of change. Since the final transient correction amount is set by converting the amount into a correction amount per constant crank angle based on the engine rotation speed, an opportunity to calculate the transient correction amount is secured even when the engine is running at low speed. For example, at the beginning of acceleration, a transient correction amount is quickly added to increase the amount of fuel, which has the effect of avoiding a lean misfire at the beginning of acceleration.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of the present invention, FIG. 2 is a system schematic diagram showing an embodiment of the present invention, FIGS. 3 to 6 are flowcharts showing control details in the above embodiment, and FIG. The figure is a diagram showing the relationship between the evaporation rate and deposition rate and the intake pressure when deriving the theoretical formula for the wall flow correction amount.
FIG. 8 is a time chart for explaining problems in conventional correction control. 1...ll connection 7...throttle valve 8...
Throttle sensor 9... Intake pressure sensor 10.
...Fuel injection valve 11...Control unit 1
5... Crank angle sensor patent applicant Fujio Sasashima, agent of Japan Electronics Co., Ltd. Patent attorney Figure 2 Figure T/12 #' in Figure 3) 3 Figure 4 Figure 5

Claims (2)

[Claims] (1) Engine operating condition detection means for detecting engine operating conditions related to the intake air amount of the engine, and calculating engine load parameters at regular intervals based on the engine operating conditions detected by the engine operating condition detection means. an engine load parameter calculation means; a change amount calculation means for calculating the amount of change per the certain period of time in the engine load parameter calculated by the engine load parameter calculation means; and a change amount calculation means based on the change amount calculated by the change amount calculation means. a time unit correction amount calculation means for calculating a time unit transient correction amount based on the time unit correction amount calculation means, and converting the time unit transient correction amount calculated by the time unit correction amount calculation means into a transient correction amount per constant crank angle based on the engine rotation speed. a transient correction amount calculation means for setting a final transient correction amount by the transient correction amount calculation means; and a transient correction control means for correcting and controlling the fuel supply amount based on the transient correction amount calculated by the transient correction amount calculation means. A fuel supply control device for an internal combustion engine, characterized in that: (2) attenuation correction amount calculation means for calculating an attenuation correction amount by decreasing the transient correction amount based on a predetermined damping characteristic value at each constant crank angle; and attenuation calculated by the attenuation correction amount calculation means. The correction amount is compared with the latest transient correction amount calculated by the transient correction amount calculation means, and when the attenuation correction amount is larger, the attenuation correction is performed instead of the transient correction amount calculated by the transient correction amount calculation means. 2. The fuel supply control device for an internal combustion engine according to claim 1, further comprising attenuation control means for forcibly setting the amount to the final transient correction amount.