JPH0615828B2 - Fuel injection control device for internal combustion engine - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a fuel for an internal combustion engine configured to determine an optimum fuel injection amount by correcting the basic injection amount according to the operating state of the engine during a transition. The present invention relates to an injection control device.

(Prior Art) Generally, the deviation of the air-fuel ratio from the target air-fuel ratio during acceleration / deceleration of the engine is mostly due to the quantitative change of the adhered fuel and the floating fuel adhering to the intake manifold of the intake system and the intake port. Yes, the amount of adhered and floating fuel varies greatly depending on the operating state of the engine. In addition, the amount of adhered and floating fuel does not change stepwise with respect to changes in the operating state, but changes with a certain delay, and the time constant of this delay is also not constant. Further, the change in the amount of adhered and floating fuel depends not only on the change in the operating state but also on the magnitude of the difference between the amount at that time and the amount in the equilibrium state (steady state).

Therefore, as a conventional example, for example, during a transition, a change in adhesion or floating fuel is approximately obtained from a change in intake pipe pressure and accelerator opening, and fuel injection amount is accelerated and decelerated and decelerated while warming up the engine. In JP-A-58-144632 and JP-A-58-144634, correction factors for acceleration increase and deceleration decrease are further corrected by a correction factor according to the cooling water temperature.
No. 58-144636, No. 58-144637 and No. 58-150033, each gazette). Further, Japanese Patent Laid-Open No. 57-24426 discloses a technique for estimating the amount of adhered and floating fuel at that time from the basic fuel injection amount during acceleration / deceleration and the temperature of the intake pipe wall and correcting the increase / decrease of fuel. Have been described.

Specifically, the basic fuel injection pulse width t during acceleration / deceleration is smoothed to obtain the smoothing function value T _N , and the difference value ΔT between the function value T _N and the injection pulse width t and the intake pipe. Based on the wall temperature, the adhesion of the intake pipe wall and the amount of floating fuel are estimated.

(Problems to be Solved by the Invention) However, in such a conventional fuel injection control device, the adhesion of the intake system and the change in the floating fuel amount are uniquely determined only by the change in the intake pipe pressure. However, it also depends on the absolute value of the pressure in the intake pipe and the engine speed. Further, the correction magnification is not constant with respect to the cooling water temperature, but changes depending on the engine rotation speed and the like. Therefore, in the conventional control device, even if the air-fuel ratio can be controlled relatively accurately under the specific acceleration / deceleration conditions, the air-fuel ratio cannot be controlled accurately under all the acceleration / deceleration conditions. As a result, there is a problem that the harmful exhaust gas cannot be reduced sufficiently and the drivability cannot be improved sufficiently, especially in the cold state.

Further, in the conventional example, the correction is performed separately for the acceleration increase amount and the deceleration decrease amount, but in most cases the accuracy of the control is not sufficient with such one type of correction, and the correction at the time of idling may be stopped, Further, there has been conventionally proposed a control device that determines an injection amount by performing a number of corrections such as a start-up and post-start-up increase correction, an idle post-increase correction, and a fuel cut correction. However, in such a control device, not only the control configuration for determining the injection amount becomes complicated, but also the matching of the correction coefficient takes time, which causes a problem that the control cannot be performed with high accuracy.

Furthermore, in the prior art disclosed in Japanese Patent Laid-Open No. 57-24426, the basic fuel injection pulse width t during acceleration / deceleration is set.
Based on the difference value ΔT from the smoothing function value T _N-1 and the temperature of the intake pipe wall, the estimated value of the adhesion of the intake pipe wall and the floating fuel is uniquely obtained, and this estimated value is used as the basic fuel injection amount. However, since the wall flow rate newly generated by such wall flow correction is not taken into consideration, the accuracy of estimation of adhesion and floating fuel amount at each time is poor, for example,
There are problems such as insufficient correction occurring at the beginning of acceleration and excessive correction occurring at the end of acceleration.

(Means for Solving Problems) The present invention has been made for the purpose of solving such problems, and its overall configuration is shown in FIG. That is, according to the present invention, the operating state detecting means a for detecting the operating state of the engine from parameters including at least the engine speed, the engine load and the engine temperature, and the basic fuel injection amount Tp are calculated based on the operating state of the engine. The calculation is performed by the basic injection amount calculating means b, the balance amount calculating means c for calculating the intake system adhesion and the floating fuel balance amount Mφ based on the engine speed, the engine load and the engine temperature. Difference value calculating means d for calculating a difference value Mφ-M between the adhered / floating fuel equilibrium amount Mφ and the intake system adhesion / floating fuel prediction variable M at that time.
And a correction coefficient DK indicating how much the difference value Mφ-M calculated by the difference value calculation means d is reflected in the correction of the fuel injection amount.
With a correction coefficient calculating means e for calculating based on the engine speed, engine load and engine temperature, and the difference value Mφ.
-M and the correction coefficient DK, the transient correction amount calculation means f for calculating the transient correction amount DM, the transient correction amount DM calculated by the transient correction amount calculation means f, and the predictive variable M of the adhered and floating fuel. Is added in synchronism with fuel injection, and the prediction variable calculation means g for updating the prediction variable M with the added value, the basic injection amount Tp calculated by the basic injection amount calculation means b, and the transient correction amount calculation means f are added. A fuel injection amount calculation means h for calculating a fuel injection amount Ti based on the calculated transient correction amount DM and outputting an injection signal, and a fuel supply means i for supplying fuel to the engine based on the injection signal. It is a thing.

(Operation) In the present invention having such a configuration, in the transient state of the engine, the transient correction amount DM is obtained from the equilibrium amount Mφ of the wall flow and its predictive variable (corresponding to the wall flow rate) M, and the prediction Since the update timing of the variable M is synchronized with the fuel injection, as a result of performing the wall flow correction and injecting, the wall flow rate that newly changes can be obtained and reflected in the next wall flow correction. The estimation accuracy of the floating fuel amount can be improved. Therefore, since a highly accurate transient correction amount can be obtained with a simple control configuration, the accuracy of air-fuel ratio control can be significantly improved. As a result, the drivability can be improved, the amount of harmful exhaust gas can be reduced, the output can be increased, and the fuel consumption can be improved, and the matching time can be shortened by simplifying the control configuration.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

2 to 10 are views showing a first embodiment of the present invention.

First, the configuration will be described. In FIG. 2, reference numeral 21 is an internal combustion engine, and intake air is supplied to each cylinder of the engine 21 through an intake pipe 22. A fuel injection valve (fuel supply means) 23 for injecting fuel into each cylinder is attached to the intake pipe 22, and a flow rate of intake air supplied to the engine 21 is a throttle provided in a collecting portion of the intake pipe 22. Controlled by valve 24. The throttle valve 24 is linked with the accelerator pedal of the vehicle,
The valve opening Cv of the throttle valve 24 is the throttle opening sensor 25.
Detected by. The flow rate of intake air (hereinafter, intake air amount) Qa is detected by the air flow rate sensor 26.
Further, the rotation speed N of the engine 21 is detected by a crank angle sensor 27, and the crank angle sensor 27 is attached to the crank shaft of the engine 21 and has a signal disk plate 27a provided with a protrusion on its outer periphery, and the signal disk plate 27a. And a magnetic deck 27b for detecting the protrusion. Further, the temperature Tw of the cooling water flowing through the water jacket is detected by the water temperature sensor 28. The throttle opening sensor 25,
The air flow rate sensor 26, the crank angle sensor 27, and the water temperature sensor 28 constitute an operating state detecting means as a whole, and each of these signals is input to the control unit 29.

The control unit 29 has functions as basic injection amount calculation means, equilibrium amount calculation means, difference value calculation means, correction coefficient calculation means, transient correction amount calculation means, predictive variable calculation means, and fuel injection amount calculation means. , CPU30, ROM31,
It is composed of a RAM 32 and an I / O port 33. C
The PU 30 fetches external data required by the I / O port 33 in accordance with the program written in the ROM 31 and exchanges data with the RAM 32 to perform arithmetic processing and process it as necessary. The data is output to the I / O port 33. The ROM 31 stores a program for controlling the CPU 30, and the RAM 32 is constituted by, for example, a non-volatile memory and stores data used for calculation in the form of a map or the like, and the stored contents are stored in the engine.
21 Hold even after stopping. The throttle opening sensor 25, the air flow rate sensor 26, the crank angle sensor are connected to the I / O port 33.
27, each signal from the water temperature sensor 28 and signals from an air-fuel ratio sensor (not shown), an ignition switch, etc. are input, and the signal input in analog is converted to digital. Further, the injection signal Si is output from the I / O port 33 to the fuel injection valve 23.

Next, the operation will be described.

Generally, air-fuel ratio control of an internal combustion engine using a fuel injection valve is controlled by changing a duty value of an injection signal output to the fuel injection valve and adjusting a fuel injection amount.

In the case of this embodiment, the duty value of the injection signal Si is calculated by the control unit 29.

Hereinafter, this operation will be described based on the flowcharts shown in FIGS. 3 and 4. It should be noted that these flows are executed, for example, in synchronization with engine rotation.

In the flowchart showing the basic injection amount calculation routine of FIG. 3, the basic injection amount Tp and a transient correction amount DM described later are described.
And ask.

First, in P ₁ , the basic injection amount Tp is calculated according to the following equation.

However, K: a constant, P _{2 corresponds} to the adhesion of the intake system under a steady condition, the equilibrium amount (steady amount) Mφ of the floating fuel to the engine speed N, the basic injection amount Tp corresponding to the engine load, and the engine temperature. It is calculated based on the cooling water temperature Tw. Specifically, it is obtained from the flowchart showing the equilibrium amount calculation routine of FIG. That is, different cooling water temperatures Tw0 to Tw0
The equilibrium amounts Mφ0 to Mφ4 obtained as experimental values using the rotational speed N and the basic injection amount Tp as parameters for Tw4 are allocated and stored in the RAM 32, and the cooling water temperature Tw0 is stored.
The equilibrium amount Mφ is obtained by performing a linear approximation interpolation calculation by looking up from a table map according to Tw4. For example, at P ₁₁ , the cooling water temperature Tw is the cooling water temperature Tw1.
When it is above, the equilibrium amount Mφφ corresponding to the engine speed N and the basic injection amount Tp is looked up from the table map Mφφ ′ corresponding to the cooling water temperature Tw0 at P ₁₂ , and P
_{In 12} , the table map Mφ corresponding to the cooling water temperature Tw1
The equilibrium amount Mφ1 corresponding to the engine speed N and the basic injection amount Tp is looked up from 1 '(see FIG. 7). Next, at P ₁₄ , the equilibrium amount Mφ is calculated from the cooling water temperature Tw by the linear approximation interpolation calculation formula. Calculate as. Similarly, the cooling water temperature Tw is Tw2 ≦ T
When w ≦ Tw1, When Tw3 ≦ Tw <Tw2, When Tw <Tw3, As a result, the equilibrium amount Mφ is obtained.

Next, returning to the flowchart of FIG. 3 again, the correction coefficient DK is calculated at P ₃ . Here, the correction coefficient DK is a coefficient indicating a ratio of how much the intake system is adhered and the amount of floating fuel that is insufficient or excessive by the correction of the current fuel injection amount. It is determined from an experimental value based on a basic injection amount Tp corresponding to the load, a cooling water temperature Tw corresponding to the engine temperature, and a transient correction amount DM described later. Specifically, the correction coefficient DK is calculated by the flowchart showing the correction coefficient calculation routine of FIG.
First, as shown in FIG. 8, the cooling water temperature correction coefficient DkTw at P ₃₁ is a table map DKTw ′ obtained as an experimental value using the cooling water temperature Tw and the transient correction amount DM obtained in the previous calculation as parameters. from look up, as shown rotational speed correction coefficient DKN, a in FIG. 9 at P _32, looking up from the obtained table map DKN 'as experimental value and the engine speed N and basic injection quantity Tp as parameters . Then, at P ₃₃ , the correction coefficient DK is calculated according to the following equation.

DK = DKTw × DKN ... Next, again referring to the flowchart shown in FIG.
_{In step 4} , the transient correction amount DM is calculated according to the following equation, and then the routine ends.

DM = DK (Mφ-M) ... Here, M is a predictive variable that is separately calculated as described later, and this variable M has a meaning as a predictive value of the amount of adhered floating fuel in the intake system at that time. Have. Therefore,
Mφ-M means an insufficient amount or an excessive amount as compared with that in the equilibrium state of the amount of adhered and floating fuel.

Next, in the flowchart showing the fuel injection amount calculation routine of FIG. 4, the actual fuel injection amount TI and the variable M are calculated.

First, at P ₄₁ , the fuel injection amount TpF is calculated according to the following equation: TpF = Tp + DM .. Then, at P ₄₂ , the actual injection amount TI is calculated according to the following equation.

TI = TpF × α × COEF + Ts Here, α is an air-fuel ratio feedback correction coefficient increased / decreased by the output of the oxygen sensor, and COEF is a correction for giving the air-fuel ratio that gives the maximum output when the engine is fully opened, at the time of starting. Is a correction coefficient for performing the increase correction and the increase correction at low water temperature, and Ts is a voltage correction amount and is a correction coefficient that has been conventionally used.

The actual fuel injection amount TI thus a need in the P ₄₃ I /
The voltage pulse width having a predetermined duty value is stored in the output register of the O port 33, and is output from the fuel injection valve 23 as an injection signal Si. As a result, the fuel injection valve 23
A predetermined amount of fuel is injected. Next, at _P44 , the variable M is calculated according to the following equation, and then the routine ends.

M = old M + DM ... Since the transient correction amount DM is an amount corresponding to the amount of adhering intake air and the amount of change in floating fuel, the variable M, which means the amount of adhering fuel and floating fuel at this point, is corrected only by the transient correction amount DM. That is, the variable M is used in the calculation of the next transient correction amount DM as the predicted value M + DM to be used next.

In this embodiment, the rotational speed N, the basic injection amount Tp, and the cooling water temperature Tw are used to obtain the equilibrium amount Mφ and the correction coefficient DK. For example, the basic injection amount Tp is used.
Alternatively, the intake air amount Qa, the intake pipe internal pressure, the throttle valve opening Cv, or the like may be used, or the cooling water temperature Tw.
Instead of this, the temperature in the intake pipe or the like may be used.

Next, FIG. 10 shows acceleration (see FIG. 10A), deceleration (see FIG. 10B), and gear change during acceleration (see FIG. 10C). , M, Mφ-
M, DKN, DKTw, DK, DM, Tp and TpF
The respective waveforms are shown. As is clear from this figure, it is possible to obtain a highly accurate transient correction amount DM that matches the degree and conditions of acceleration and deceleration during acceleration and deceleration. Therefore, the optimum fuel injection amount TpF can be secured and the optimum air-fuel ratio can be obtained. Further, even when changing gears, it is possible to perform accurate and continuous correction without performing control such as switching between acceleration increase and deceleration decrease. As a result, it is possible to improve drivability, reduce harmful exhaust gas, increase output, and improve fuel efficiency.

Next, FIGS. 11 and 12 are views showing a second embodiment of the present invention.

This example is an example in which the control of the transient correction amount DM described above is similarly applied to correction during fuel cut and recovery.

FIG. 11 is a flowchart showing a routine similar to the injection amount calculation routine for calculating the transient correction amount DM of the basic injection amount Tp shown in FIG. 3, which is step ₅₂ and step P _53.
Differs from the routine shown in FIG.

After calculating the basic injection amount Tp in P ₅₁ , it is determined in P ₅₂ whether or not the fuel is being cut. If the fuel is not being cut,
It advances to P _54. When the fuel is being cut, the equilibrium amount Mφ is set at P ₅₃ to a predetermined value MFC, for example, zero or a value much smaller than the normal equilibrium amount Mφ, and at P ₅₅ the correction coefficient DK is set.
, The transient correction amount DM is calculated at P ₅₆ , and the routine ends. Incidentally, if the fuel cut, as in the case described above, completing the routine through P ₅₄ to P _56.

Here, normally, at the time of fuel cut and recovery, the air-fuel ratio shifts in the lean direction. This is because the adhesion of the intake system and the floating fuel are sucked into the engine 21 during the fuel cut, and at the time of recovery, the fuel injection amount corresponding to the intake air amount Qa is insufficient for reattaching to the intake system. However, in this embodiment, as shown in FIG. 12, during the fuel cut, the equilibrium amount Mφ is set to, for example, zero, so the variable M gradually becomes smaller and the equilibrium amount M becomes smaller.
It gradually approaches to φ. Therefore, when the equilibrium amount Mφ reaches a predetermined value during recovery, Mφ−M>
It becomes 0, and an appropriate increase correction is made. When the fuel cut time is short, that is, when Mφ-M does not reach a large value, when the fuel cut or recovery is started, Mφ-M at the time of recovery does not become a large value and the transient correction amount DM is small. However, in this case, since the intake system adhesion and the amount of floating fuel have not decreased so much,
Optimum correction can be performed in consideration of this.

Further, the increase correction at the time of starting the engine can be similarly performed. In this case, when the ignition switch is turned on, the variable M is set to zero in a separately provided initialization routine, so that the increase correction according to the operating state at the time of start cranking can be appropriately performed. Furthermore, even after the completion of the explosion, the appropriate correction can be similarly performed. However, in this case, in the cold start, a part of the fuel adheres to the cylinder wall and is discharged without being burned. Therefore, it is preferable to perform the increase correction accordingly.

As described above, in the present invention, various kinds of corrections that have been conventionally performed can be performed with a minimum amount of correction, and control can be performed with high accuracy. That is, the startup increase correction and the post-start increase correction are simplified (only the unburned emission amount is corrected), and the increase correction after idling is abolished.
In addition, it is unnecessary to separately perform the correction after the fuel cut, and it is not necessary to separately perform the correction during acceleration and during deceleration.

Next, FIGS. 13 and 14 are views showing a third embodiment of the present invention.

This embodiment is an example in which not only learning control during steady operation but also learning control during transient correction is performed.

FIG. 13 is a flow chart showing a feedback routine for learning control, and P _{61 to} P ₇₄ show respective steps.

First, in P ₆₁ , it is determined whether or not the feedback condition is satisfied based on the operating condition, and if so, P ₆₂
If not, go to P ₆₃ . In P ₆₃ , the steady learning result is stored in the RAM 32 according to the operating conditions.
The feedback correction coefficient α is obtained by referring to the address of, and the integrated value Σα of α and the integrated number n of α are set to zero at P ₆₄ , and this routine ends. Next, when the feedback condition is satisfied, the output O ₂ of the oxygen sensor is compared with the comparison reference value S / L at P ₆₂ , and when O ₂ <S / L, it is leaner than the theoretical air-fuel ratio. It determined to calculate the increase correction amount by the PI control at P _65. When O ₂ > S / L, it is judged to be richer than the stoichiometric air-fuel ratio, and at P ₆₆ , the reduction correction amount is calculated by PI control. Next, at P ₆₇ , the increase / decrease correction amount P + I is added to the old feedback correction coefficient to obtain a new feedback correction coefficient α, and the _routine proceeds to P ₆₈ . At P ₆₈ , the absolute value | DM | of the transient correction amount DM is compared with the comparison reference value LGDM, and when | DM | <LGDM, it is determined that there is no transient time (a steady state), and at P ₆₉ , α Integrated value (Σα = Σ
The integrated number n (n = n + 1) of α + α) and α is calculated and the process proceeds to P ₇₀ . When | DM |> LGDM, it is determined that there is a transition, and the integrated number n is compared with the learning determination circuit LGn in P ₇₁ .
When n> LGn, the average value of α at P ₇₂ (= Σα
/ N) and to calculate advances to P _72.

Performing rewriting address RAM32 corresponding to the transient learning coefficient CMφ1~GMφn using P ₇₃ in average feedback correction coefficient. Transient learning coefficients GMφ1 to GMφn are respectively assigned to the addresses of the RAM 32 according to the cooling water temperature Tw, and the contents of the address according to the cooling water temperature Tw are rewritten. That is, the average feedback correction coefficient and the value of the RAM 32 corresponding to the cooling water temperature Tw may be used and the difference may be added to the value of the RAM.
When the rewriting of the RAM 32 is completed, the integrated value Σα and the integrated number n are set to zero at P ₇₄ and the process proceeds to P ₇₀ . N <LGN at P ₇₁
In case of, the number of samples is small and the accuracy is judged to be poor, and the integrated value Σα and the integrated number n are set to zero and the process proceeds to P ₇₀ . Next, after the steady learning calculation is performed at P ₇₀ , this routine is finished. Although the content is omitted in P ₇₀ , the value in the RAM 32 is rewritten using the average feedback correction coefficient in the same manner as in the case of the transition, when it is determined to be in the steady state. It is preferable that the transient learning coefficients GMφ1 to GMφn are not assigned, but are assigned according to the engine speed N and the basic injection amount Tp.

Next, FIG. 14 is a flow chart showing a calculation routine for calculating the basic injection amount Tp and the transient correction amount DM. This calculation routine differs from the calculation routine shown in FIG. 3 in the following points. That is, in this routine, the transient learning coefficient GMφ is referred to in step P ₈₄ , and the transient correction amount DM is calculated in accordance with the following equation in step P ₈₅ .

DM = DK × (Mφ × GMφ−M) The reference of the transient learning coefficient GMφ is the address of the RAM 32 corresponding to the current cooling water temperature Tw obtained by learning the cooling water temperature Tw in the feedback routine. It is done by taking it out from. In such transient learning control, the adherence of the intake system and the amount of floating fuel change due to the nature of the fuel, and this changes over time due to the amount of deposit adhered to the intake system. Has that purpose. Here, if poor fuel is used,
During acceleration, the air-fuel ratio shifts in the lean direction. Therefore, in this embodiment, the transient learning coefficient GMφ is rewritten to a larger value by using the average feedback correction coefficient that has a larger value during the transition during the feedback control. Therefore, since the transient correction amount DM also becomes large, it is corrected that the air-fuel ratio becomes lean during acceleration. Further, the accuracy of the transient correction amount DM can be increased little by little as learning is repeated.

As described above, the transient learning coefficient GMφ is used by the learning control to provide the optimum transient correction amount DM even when the poor fuel is used and the deposit is attached to the intake system. You can Therefore, the accuracy of air-fuel ratio control can be improved.

(Effects) As described above, according to the present invention, not only during acceleration / deceleration of the engine but also during fuel cut recovery, when poor fuel is used, or when deposits are attached to the intake system, the air-fuel ratio Since the control accuracy can be greatly improved, it is possible to improve drivability, reduce harmful exhaust gas amount, and increase output.

Further, since the increase correction according to the cooling water temperature can be greatly reduced to prevent breathing during acceleration during warm-up, it is possible to improve fuel efficiency and prevent smoldering of the plug accordingly.

Furthermore, since the various corrections that have been conventionally performed can be limited to the minimum correction, the control configuration can be simplified,
The number of matching steps can be reduced and the matching time can be shortened.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of the present invention, FIGS. 2 to 10 are diagrams showing a first embodiment of the present invention, FIG. 2 is a schematic configuration diagram thereof, and FIGS. 3 and 4 are fuels. Each flow chart showing the main routine of injection control, FIG. 5 is a flow chart showing a subroutine for calculating the transient correction amount, FIG. 6 is a flow chart for showing a subroutine for calculating the correction coefficient, and FIG. 7 is an example of the equilibrium amount. Table map showing,
8 is a table map of the cooling water correction coefficient, FIG. 9 is a table map of the rotation speed correction coefficient, FIG. 10 (A),
(B) and (C) are graphs showing waveforms of signals at acceleration, low speed, and gear change, and FIGS. 11 and 12 are diagrams showing a second embodiment of the present invention. Is a flow chart showing a main routine of fuel injection control at the time of fuel cut recovery, FIG. 12 is a graph showing waveforms of respective signals at the time of fuel cut recovery, and FIGS. 13 and 14 show a third embodiment of the present invention. FIG. 13 is a flowchart showing a feedback routine of learning control, and FIG. 14 is a flowchart showing a main routine of fuel injection control by learning control. 21 ... Engine (engine), 23 ... Fuel injection valve (fuel supply means), 25, 26, 27, 28 ... Operating state detection means, 29 ... Control unit (basic injection amount calculation means, balance amount calculation means) , Difference value calculation means, correction coefficient calculation means, transient correction amount calculation means, prediction variable calculation means, fuel injection amount calculation means).

Continuation of front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display area F02D 45/00 F 7536-3G

Claims (1)

[Claims] 1. An operating state detecting means for detecting an operating state of an engine from parameters including at least engine speed, engine load and engine temperature; and b) a basic fuel injection amount based on the operating state of the engine. Tp) basic injection amount calculating means, c) balance amount calculating means for calculating intake system adhesion, floating fuel equilibrium amount (Mφ) based on engine speed, engine load and engine temperature, and d) Difference value calculation for calculating the difference value (Mφ-M) between the adhesion amount calculated by the balance amount calculation means, the floating fuel equilibrium amount (Mφ) and the intake system adhesion at that time, and the floating fuel prediction variable (M) And e) a correction coefficient (D) indicating how much the difference value (Mφ-M) calculated by the difference value calculation means is reflected in the correction of the fuel injection amount.
Correction coefficient calculation means for calculating K) based on the engine speed, engine load and engine temperature; and f) a transient correction amount (DM) based on the difference value (Mφ-M) and the correction coefficient (DK). ), And a transient correction amount (DM) calculated by the transient correction amount calculation device.
And the predictive variable (M) of the adhered and floating fuel in synchronism with fuel injection, and the predictive variable calculating means for updating the predictive variable (M) with the added value; and h) the basic injection amount calculating means. Calculated basic injection amount (T
p) and a fuel injection amount calculation means for calculating a fuel injection amount (Ti) based on the transient correction amount (DM) calculated by the transient correction amount calculation means, and outputting an injection signal, i) based on the injection signal A fuel injection control device for an internal combustion engine, comprising: a fuel supply unit configured to supply fuel to the engine.