JP2527738B2 - Fuel control device for internal combustion engine - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a fuel control for an internal combustion engine, which detects an intake air amount of the internal combustion engine by an intake air amount sensor and controls the fuel supply amount of the internal combustion engine by the detection output. It relates to the device.

[Conventional technology]

An intake air amount sensor (hereinafter abbreviated as AFS) is arranged upstream of the throttle valve when performing fuel control of the internal combustion engine,
The amount of intake air per intake air is obtained from this information and the engine speed to control the supplied fuel amount.

By the way, when an AFS is arranged upstream of the throttle valve in the air intake passage to detect the intake air amount of the internal combustion engine, when the throttle opens suddenly, the intake passage between the throttle valve and the engine is opened. Since the amount of air to be filled is also measured, the amount of air that is actually sucked into the internal combustion engine is more than the amount actually measured, and if the fuel amount is controlled as it is, there is a problem that it becomes overrich. Therefore, conventionally, the output of AFS, that is, the detected intake air amount at a predetermined crank angle is AN _(t) , and the air amount taken by the internal combustion engine at the predetermined crank angle n-1 and n times is AN _{(n-1), respectively. )} and aN _(n), aN _(n) is calculated by the formula of _{aN (n) = K 1 ×} aN (n-1) + K 2 × aN (t) when the filter constant was K, the aN _(n) is used to perform fuel control, which smoothes the intake air amount for each predetermined crank angle and performs appropriate fuel control.

Further, the output of the AFS has non-linearity that is not proportional to the air amount, and in order to correct this, conventionally, the above-described filter processing was performed and then linearization processing was performed.

In general, the Karman vortex flowmeter is a linear sensor that basically produces a frequency output that is almost proportional to the intake air amount, but has a non-linear characteristic in the low flow rate range and has a frequency higher than the actual intake air amount. Produces output. Therefore, in the transitional period, the Kalman intake air amount sensor generates a frequency output that is higher than the actual value, and the output value after the filtering process also shows a value that is higher than the actual value.

That is, since the degree of non-linearity varies depending on the air amount, and the weight of the air amount with respect to the output of the intake air amount sensor differs, filtering the intake air amount sensor output as it is results in averaging different weights. Therefore,
Even if linearization correction is performed after the filter processing, the intake air amount cannot be corrected correctly.

[Problems to be solved by the invention]

As described above, the fuel control device for the conventional internal combustion engine performs the linearization processing after performing the filtering processing, and when the output of the AN detection means is filtered, it is smoothed and becomes rather inaccurate as an instantaneous value. , An accurate AN value could not be obtained even if this was linearized and corrected.

The present invention has been made to solve the above problems, it is possible to detect the accurate intake air amount of the engine,
An object of the present invention is to obtain a fuel control device for an internal combustion engine that can perform accurate fuel control in response to this.

[Means for solving problems]

The fuel control device for an internal combustion engine according to the present invention includes an intake air amount sensor arranged upstream of a throttle valve of the internal combustion engine for detecting the amount of air flowing into an intake pipe, and a crank angle sensor for detecting a predetermined crank angle of the internal combustion engine. And intake air calculating means for calculating the intake air amount Qa (n) flowing into the intake pipe within a predetermined crank angle section in synchronization with the crank angle sensor, and the output of the intake amount sensor in synchronization with the crank angle sensor. Including coefficient calculation means for calculating the linearization correction coefficient KL according to
Intake air amount linearization correcting means for linearly correcting the intake air amount Qa (n) by KL × Qa (n), and n of a predetermined crank angle
Let Qe (n-1) and Qe (n) be the intake air amounts sucked into the cylinder of the internal combustion engine at the -1st time and the nth time, respectively, and relate to at least the volume downstream of the throttle valve of the internal combustion engine and the cylinder volume of the internal combustion engine. Constant K1
And K2, the intake air that filters the intake air amount KL × Qa (n) that has been linearized and corrected based on the following equation: Qe (n) = K1 × Qe (n-1) + K2 × KL × Qa (n) The intake air amount filter calculation process includes an amount filter calculation processing unit and a control unit that controls the amount of fuel supplied to the internal combustion engine based on the intake air amount Qe (n) calculated by the intake air amount filter calculation processing unit. The means sequentially updates the intake air amount Qe (n) by using the intake air amount Qe (n) calculated this time as the intake air amount Qe (n-1) in the next filter calculation process.

[Action]

In the present invention, the filter processing is performed after the linearization correction of the output of the intake air amount calculation means is performed,
The linearization correction is accurately performed at each instant.

〔Example〕

 Embodiments of the present invention will be described below with reference to the drawings.

FIG. 3 shows a model of the intake diameter of the internal combustion engine, where 1 is the internal combustion engine, has a volume of Vc per stroke, and is a Karman vortex flowmeter (that is, an intake air amount sensor) AFS13, throttle valve 12, surge tank 11 Also, air is taken in through the intake pipe 15, and fuel is supplied by the injector 14.
Further, here, the volume from the throttle valve 12 to the internal combustion engine 1 is Vs. 16 is an exhaust pipe.

FIG. 4 shows the relationship of the intake air amount with respect to a predetermined crank angle in the internal combustion engine 1, and (a) shows the predetermined crank angle (hereinafter referred to as SGT) of the internal combustion engine 1. (B) is A
The air amount Qa passing through the FS13, (c) shows the air amount Qe taken by the internal combustion engine 1, and (d) shows the output pulse f of the AFS13.
Also, the n-2 to _n-1 rising period of SGT is t _n-1 ,
The rising period of the n-1 to n-th times is t _n, and the intake air amount passing through the AFS 13 in the periods t _n-1 and t _n is Qa _(n-1) and
Qa _(n) and the amounts of air taken in by the internal combustion engine 1 in the periods t _n-1 and t _n are Qe _(n-1) and Qe _(n) , respectively. Furthermore, the period t _n-1
The average pressure and the average intake air temperature in the surge tank 11 at times t and t _n are Ps _(n-1) and Ps _(n) and Ts _(n-1) and Ts _(n) , respectively. Here, for example, Qa _(n-1) corresponds to the number of output pulses of the AFS ₁₃ during t _n-1 . Also, since the rate of change of intake air temperature is small, _assuming that Ts _(n-1) ≈ Ts _(n) and the charging efficiency of the internal combustion engine 1 is constant, Ps _(n-1)・ Vc = Qe _(n-1)・R · T _{s (n)} (1) Ps _(n) · Vc = Qe _(n) · R · T _{s (n)} (2) However, R is a constant. Then, the amount of air accumulated in the surge tank 11 and the intake pipe 15 during the period t _n is changed to ΔQ a _(n)
Then And, from equations (1) to (3), Is obtained. Therefore, the air amount Qe _{(n) taken in} by the internal combustion engine 1 in the period t _n can be calculated by the equation (4) based on the air amount Qa _(n) passing through the AFS 13. Here, Vc = 0.
When 5l and Vs = 2.5l, Qe _(n) = 0.83 x Qe _(n-1) + 0.17 x Qa _(n) (5). FIG. 5 shows a state where the throttle valve 12 is opened. In FIG. 5, (a) is the opening of the throttle valve 12, and (b) is the intake air amount Qa passing through the AFS 13.
Therefore, due to the above-mentioned reason (the amount of air filled in the intake passage), overshoot (rapid increase) occurs. (C) is (4)
Is the air quantity Qe taken in by the internal combustion engine 1 corrected by the equation,
(D) is the pressure P of the surge tank 11.

The above calculation processing is a general schematic description, and in the embodiment of the present invention, the intake air amount Qa in the above equation (5) is
(N) will be corrected in advance by the linearization correction coefficient KL (described later). Hereinafter, embodiments of the present invention will be described in detail. FIG. 1 shows the structure of a fuel control device for an internal combustion engine according to the present invention. 10 is an air cleaner arranged upstream of the AFS 13, and AFS 13 is shown in FIG. 4 according to the amount of air taken into the internal combustion engine 1. The crank angle sensor 17 outputs a pulse as shown in d), and the crank angle sensor 17 responds to the rotation of the internal combustion engine 1 by a pulse as shown in FIG. 4 (a) (for example, a crank angle of 180 ° from one pulse rising to the next rising). Is output). Reference numeral 19 denotes an intake air amount calculation means (hereinafter referred to as AN detection means) for calculating an intake air amount Qa (n) flowing into the intake pipe based on the output of the intake air amount sensor 13, and in synchronization with the crank angle sensor 17. In order to calculate the intake air amount Qa (n) flowing into the intake pipe within the predetermined crank angle section, AFS1
From the output of 3 and the output of the crank angle sensor 17, the number of output pulses of the AFS 13 that falls within a predetermined crank angle of the internal combustion engine 1 is calculated. Reference numeral 20 denotes intake air amount linearization correction means (hereinafter referred to as AN correction means) that performs linearization correction of the output of the AN detection means 19, and performs linearization correction by the output of the intake air amount sensor 13 in synchronization with the crank angle sensor 17. A coefficient calculation means for calculating the coefficient KL is included, and the intake air amount Qa (n) is linearized and corrected by KL × Qa (n). 21 is the intake air amount KL from the AN correction means 20
Intake air amount filter calculation processing means (hereinafter referred to as AN calculation means) for filtering × Qa (n), and the same calculation as equation (5) from linearized and corrected intake air amount KL × Qa (n) Then, the number of pulses corresponding to the output of the AFS 13 corresponding to the amount of air considered to be taken in by the internal combustion engine 1 is calculated. That is, assuming that a general filter coefficient is K1, the above equation (5) is expressed as the following equation (6) using the linearization correction coefficient KL.

Qe (n) = K1 × Qe (n-1) + (1-K1) × KL × Qa
(N) (6) However, (1-K1) can be expressed as another filter coefficient K2. Therefore, the intake air amount taken into the cylinder of the internal combustion engine at the (n-1) th and nth times of the predetermined crank angle is defined as Qe (n-1), Qe (n), and at least at the downstream of the throttle valve of the internal combustion engine. Intake linearized and corrected based on the following equation, Qe (n) = K1 × Qe (n-1) + K2 × KL × Qa (n), from constants K1 and K2 determined in relation to the volume and the cylinder volume of the internal combustion engine. The air amount KL × Qa (n) is filtered. As is well known below, at the time of the next filter calculation processing, the intake air amount Qe calculated this time
By substituting (n) as the previous intake air amount Qe (n-1) in the above equation, the intake air amount Qe after the filtering process is performed.
(N) is updated sequentially. Further, the control means 22 uses the output of the AN calculation means 21, the output of the water temperature sensor 18 (for example, a thermistor) that detects the cooling water temperature of the internal combustion engine 1, and the output of the idle switch 23 that detects the idle state, to determine the internal combustion engine 1
The drive time of the injector 14 is controlled in accordance with the amount of air taken in by the engine, and thereby the amount of fuel supplied to the internal combustion engine 1 is controlled.

FIG. 2 shows a more specific structure of this embodiment, where 30 is an AF.
It is a control device that receives the output signals of S13, the water temperature sensor 18, the idle switch 23, and the crank angle sensor 17, and controls the four injectors 14 provided for each cylinder of the internal combustion engine. It is realized by a microcomputer (hereinafter abbreviated as CPU) 40 having ROM 41 and RAM 42, which corresponds to the AN detection means 19 to the control means 22 in the figure. Further, 31 is a frequency divider connected to the output of the AFS13, 32 is an exclusive OR gate in which the output of the frequency divider 31 is one and the other input terminal is connected to the input P1 of the CPU 40, and its output terminal Is connected to the counter 33 and the output P3 of the CPU 40. 34a is an interface connected between the water temperature sensor 18 and the A / D converter 35, 34b is an interface connected between the idle switch 23 and the CPU 40, 36 is a waveform shaping circuit, and the output of the crank angle sensor 17 is input. And its output is CPU4
It is input to the interrupt input P4 of 0 and the counter 37. Also 38
Is a timer connected to the interrupt input P5, 39 is an A / D converter that A / D converts the voltage of the battery (not shown) and outputs it to the CPU 40, 43 is a timer provided between the CPU 40 and the driver 44, The output of driver 44 is connected to each injector 14.

Next, the operation of the above configuration will be described. The output of AFS13 is 2
The frequency is divided by the frequency divider 31 and input to the counter 33 via the exclusive OR gate 32 controlled by the CPU 40. Counter 33 measures the period between the falling edges of the output of gate 32. The CPU 40 inputs the falling edge of the gate 32 to the interrupt input P3, performs an interrupt process every output pulse cycle of the AFS13 or every frequency divided by two, and measures the cycle of the counter 33. The output of the water temperature sensor 18 is converted into a voltage by the interface 34a, converted into a digital value by the A / D converter 35 at predetermined time intervals, and taken into the CPU 40. The output of the crank angle sensor 17 is output to the interrupt input P4 of the CPU 40 and the counter 37 via the waveform shaping circuit 36. Idle switch
The output of 23 is input to the CPU 40 via the interface 34b. The CPU 40 performs an interrupt process for each rising of the crank angle sensor 17, and detects the cycle between the rising of the crank angle sensor 17 from the output of the counter 37. The timer 38 is CP every predetermined time
Generates an interrupt signal to interrupt input P5 of U40. A / D converter
39 performs A / D conversion of a battery voltage (not shown), and the CPU 40 takes in data of this battery voltage at predetermined time intervals. Timer 43
Is preset in the CPU 40 and is output from the output port P2 of the CPU 40 to output a predetermined pulse width. This output drives the injector 14 via the driver 44.

Next, the operation of the CPU 40 will be described with reference to the flowcharts of FIGS. First, FIG. 6 shows the main program of the CPU 40. When a reset signal is input to the CPU 40, the RAM 42, the input / output port, etc. are initialized in step 100, and the output of the water temperature sensor 18 is A / D converted in step 101. , WT is stored in the RAM 42. In step 102, the battery voltage is A / D converted and stored in the RAM 42 as VB. Step
At 103, the basic drive time conversion coefficient K _P is corrected by the water temperature data WT and stored in the RAM 42 as the drive time conversion coefficient K ₁ .
In step 104, the data table f ₃ stored in advance in the ROM 41 is mapped from the battery voltage data VB, and the waste time
Calculate T _D and store in RAM 42. After the processing of step 104, the processing of step 101 is repeated again.

Figure 7 illustrates the interrupt processing for the output signal of the interrupt inputs P ₃ That AFS13. In step 201, the output T _F of the counter 33 is detected and the counter 33 is cleared. This T _F is the period between the rising edges of the gate 32. In step 202, the integrated value S of the period T _F is obtained, and in step 203 it is judged whether or not the frequency division flag is set. If it is set, in step 204 the pulse number N
Is added to 2, and in the case of resetting, 1 is added to the pulse number N in step 205. In step 206, it is determined whether N is 16 or more. If N is 16 or more, the output frequency F _S of the AFS 13 is calculated by N / S in step 207, and S, N are cleared in step 208. If the frequency division flag in the RAM 42 is set in step 209, the accumulated pulse data P _R is multiplied by double the remaining pulse data P _D in step 211 to obtain new accumulated pulse data P _R. The integrated pulse data P _R is used to integrate the number of pulses of the AFS 13 output during the rising of the crank angle sensor 17, and is processed 156 times as much as one pulse of the AFS 13 for the convenience of processing. If the division flag is reset in step 209, the remaining pulse data P _D is added to the integrated pulse data P _R in step 213. Step 214
Then, 156 is set to the remaining pulse data P _D. Step 2
T _F > 2mse if the division flag is reset at 15
c, if set, step if T _F > 4msec
217, otherwise go to step 216. Step
In 216, the division flag is set, and if the previous division flag was reset in step 219, the cycle T _{F is set} to 1 in step 220.
Set to / 2 for the output pulse period T _A, and if set, complete the process. In step 217, the frequency division flag is cleared, P1 is inverted in step 218, and if the previous frequency division flag is reset in step 221, the cycle T _F is doubled in step 222 to be the output pulse cycle T _A, and set. If so, the process is completed. Therefore, in the case of the processing of step 216, A
Interrupt input P3 at the timing of FS13 output pulse divided by 2
When the signal comes in and the process of step 217 is performed, A
A signal is input to interrupt input P3 for each output pulse of FS13. After the processing of steps 220 and 222, the interrupt processing is completed.

FIG. 8 shows an interrupt process when an interrupt signal is generated at the interrupt input P4 of the CPU 40 by the output of the crank angle sensor 17.
In step 301, the cycle between the rising edges of the crank angle sensor 17 is read from the counter 37, stored as the cycle T _R in the RAM 42, and the counter 37 is cleared. If there is an AFS13 output pulse in the cycle T _R in step 302, in step 303 the time t ₀₁ of the AFS13 output pulse immediately before that and the crank angle sensor
The time difference Δt = t ₀₂ -t ₀₁ of this interruption time t ₀₂ 17 computes, which was a period T _S, the period T when the output pulse of _R in the AFS13 is not the period T _R of the period T _S And Step 305 at 1
From the calculation of 56 × T _S / T _A , the time difference Δt is converted into the output pulse data ΔP of AFS13. That is, the pulse data ΔP is calculated assuming that the output pulse cycle of the previous AFS13 and the output pulse cycle of the current AFS13 are the same. In step 306, if the pulse data ΔP is smaller than 156, it is clipped to step 308, and if it is large, ΔP is clipped to 156 in step 307. In step 308, the pulse data ΔP is subtracted from the remaining pulse data P _D to obtain new remaining pulse data ΔP. Step
In 309, if the remaining pulse data P _D is positive, step 313a
To, in the case of other calculated values of pulse data ΔP same west as P _D pulse data ΔP in step 310 because too much greater than the output pulse of AFS13, the rest pulse data to zero at step 312. In step 313a, it is determined whether or not the frequency division flag is set. In the case of resetting, the pulse data ΔP is added to the integrated pulse data P _R in step 313b, and in the case of setting, 2 is added to P _R in step 313c.・ ΔP
Is added to obtain new integrated pulse data P _R. The data P _R is, AFS13 between the rise of the current crank angle sensor 17
Corresponds to the number of pulses considered to have been output by.

After obtaining P _R , the pulse constant K _L stored for the frequency F _S is obtained from the map f ₁ shown in FIG. 9 (step 31
4) By multiplying this K _L with P _R in step 315, the intake air amount Q _R between the crank angles (which has been linearized and corrected) is obtained, and then the filtering process is performed.

In steps 316 to 318, the calculation corresponding to the equation (5) is performed. That is, based on the load data AN and the intake air amount Q _R calculated up to the last rise of the crank angle sensor 17, if the idle switch 23 is ON, it is determined that the idle state is AN = K ₂
AN + (1-K ₂ ) Q _R is calculated, and if the idle switch 23 is off, K ₁ AN + (1-K ₁ ) Q _R is calculated (K ₁ > K ₂ ), and the results are Use load data AN.

Here, when the equations of steps 317 and 318 are made to correspond to the equation (6) related to the equation (5), the load data AN is the intake air amount.
Corresponds to Qe (n), K ₁ and K ₂ corresponds to the filter coefficient K1, Q _R would correspond to the intake air amount KL × Qa corrected (n). If the load data AN is larger than the predetermined value α in step 319, it is clipped to α in step 320 so that the load data AN does not become larger than the actual value even when the internal combustion engine 1 is fully opened. In step 321, the integrated pulse data P _R is cleared. Step 322 loads the data AN and the drive time conversion coefficient K _1, performs a calculation of the time driving from the dead time T _D data _{T 1 = AN · K 1 +} T D, set the drive time data T ₁ in step 323 to the timer 43 Then, in step 324, timer 43
Injector according to data T ₁ by triggering
Four 14's are driven simultaneously, and the interrupt process is completed.

FIG. 10 shows the timing when the frequency division flag is cleared in the processing of FIGS. 6 to 8, and (a) shows the frequency divider 31.
And the output of the crank angle sensor 17 is shown in (b). (C) shows the remaining pulse data P _D, which is 1 at each rise and fall of the frequency divider 31 (rise of the output pulse of the AFS13).
It is set to 56, and for example every time the crank angle sensor 17 rises,
The calculation result is changed to P _Di = P _D −156 × T _S / T _A (this corresponds to the processing of steps 305 to 312). (D) shows a change in the integrated pulse data P _R , and shows how the remaining pulse data P _D is integrated every time the output of the frequency divider 31 rises or falls.

As described above, in the above-described embodiment, the value of K in the correction formula for the intake air amount of the internal combustion engine is made small during the idle operation, so that the delay of the intake air amount can be made small and the phase can be made to the lead side. Therefore, the pulse width signal is also advanced as shown by f, and the air-fuel ratio can be made thin when N _e is high as shown in h, and can be made thick when N _e is low, which promotes fluctuations in the rotational speed. It is possible to obtain a stable rotation speed without being caused. Further, the detected A / N value is subjected to the linearization correction and then the filter processing is performed, and the correct instantaneous value is linearized and corrected to obtain the correct A / N value.

In the above embodiment, the output pulses of the AFS13 during the rising of the crank angle sensor 17 are counted, but this may be during the falling, and the AFS13 for several cycles of the crank angle sensor 17 may be counted.
The number of output pulses may be counted. Although the output pulses of the AFS13 are counted, the number of output pulses may be multiplied by a constant corresponding to the output frequency of the AFS13.
Further, the same effect is obtained by using the ignition signal of the internal combustion engine 1 instead of the crank angle sensor 17 to detect the crank angle. Further, the number of revolutions and the condition for stopping the vehicle may be added to the idle determination, and the coefficient K may be further corrected according to the number of revolutions, the load, the gear ratio, and the like.

〔The invention's effect〕

As described above, according to the present invention, an intake air amount sensor arranged upstream of a throttle valve of an internal combustion engine for detecting the amount of air flowing into the intake pipe, and a crank angle sensor for detecting a predetermined crank angle of the internal combustion engine. , Intake air amount calculation means for calculating the intake air amount Qa (n) flowing into the intake pipe within a predetermined crank angle section in synchronization with the crank angle sensor, and output of the intake amount sensor in synchronization with the crank angle sensor The coefficient calculation means for calculating the linearization correction coefficient KL by
(N) intake air amount linearization correction means for linearly correcting the intake air amount Qa (n), and n-1 of a predetermined crank angle.
Let Qe (n-1) and Qe (n) be the intake air amounts taken into the cylinders of the internal combustion engine at the n-th time and the n-th time, respectively.
From the constants K1 and K2 determined in relation to at least the volume downstream of the throttle valve of the internal combustion engine and the cylinder volume of the internal combustion engine, the following equation, Qe (n) = K1 × Qe (n-1) + K2 × KL × Qa (n) Based on the intake air amount filter calculation processing unit that filters the intake air amount KL × Qa (n) linearized and corrected based on the above, and the intake air amount Qe (n) calculated by the intake air amount filter calculation processing unit, The intake air amount filter calculation processing means includes the intake air amount Qe (n) calculated this time, and the intake air amount Qe (n in the next filter calculation processing. As -1), the intake air amount Qe (n) is sequentially updated, and the intake air amount Qa (a) calculated by the intake air amount calculating means is filtered after linearization correction. Correct instantaneous value is obtained and fuel control It can be done more accurately.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an apparatus according to the present invention, FIG. 2 is a configuration diagram showing an embodiment as a specific example of the fuel control apparatus for the internal combustion engine, and FIG. 3 is an intake system for the internal combustion engine according to the present invention. FIG. 4 is a configuration diagram showing the model of FIG. 4, FIG. 4 is a diagram showing the relationship of the intake air amount with respect to the crank angle, FIG. 5 is a waveform diagram showing the change of the intake air amount during the transient of the internal combustion engine, and FIGS. FIG. 8 is a flow chart showing the operation of the fuel control system for an internal combustion engine according to an embodiment of the present invention, FIG. 9 is a diagram showing the relationship between the pulse constant and the AFS output frequency of the fuel control system for the internal combustion engine, and FIG. 9 is a timing chart showing the timing of the flow of FIGS. 1 ... Internal combustion engine, 12 ... Throttle valve, 13 ... Air flow sensor (Karman vortex flowmeter), 14 ... Injector, 15 ... Intake pipe, 17 ... Crank angle sensor, 19 ... AN
Detecting means (intake air amount calculating means), 20 ... AN correcting means (intake air amount linearizing correcting means), 21 ... AN calculating means (intake air amount filter calculating processing means), 22 ... Control means, 23
…… Idle switch. In the drawings, the same reference numerals denote the same or corresponding parts.

Claims (1)

(57) [Claims] 1. An intake air amount sensor arranged upstream of a throttle valve of an internal combustion engine for detecting the amount of air flowing into an intake pipe; a crank angle sensor for detecting a predetermined crank angle of the internal combustion engine; and a crank angle sensor. Intake air amount calculation means for calculating the intake air amount Qa (n) flowing into the intake pipe in the section of the predetermined crank angle in synchronization with, and the output of the intake amount sensor in synchronization with the crank angle sensor. A coefficient calculation means for calculating a linearization correction coefficient KL according to KL × Qa (n), and an intake air amount linearization correction means for linearly correcting the intake air amount Qa (n); The intake air amount taken into the cylinder of the internal combustion engine at the (n-1) th time and the nth time respectively
Qe (n-1) and Qe (n), at least from constants K1 and K2 determined in relation to the volume of the internal combustion engine downstream of the throttle valve and the cylinder volume of the internal combustion engine,
The linearized and corrected intake air amount KL × Qa (n) based on the following equation, Qe (n) = K1 × Qe (n-1) + K2 × KL × Qa (n)
Intake air amount filter calculation processing means for filtering the intake air amount, and control means for controlling the amount of fuel supplied to the internal combustion engine based on the intake air amount Qe (n) calculated by the intake air amount filter calculation processing means. The intake air amount filter calculation processing means uses the intake air amount Qe (n) calculated this time as the intake air amount Qe (n-1) for the next filter calculation process, and the intake air amount Qe (n).
Are sequentially updated. A fuel control device for an internal combustion engine, wherein: