JPH01315644A - Fuel injection quantity controller of internal combustion engine - Google Patents

Abstract

PURPOSE:To minimize the shortage of fuel and prevent the emission of exhaust gas from aggravating by forecasting the future physical quantity concerning to the quantity of intake air on the bases of the present and the past data of the sampled physical values and injecting fuel by the quantity corresponding to the forecasted value. CONSTITUTION:There is provided a sampling means A which samples the physical quantity concerning to the quantity of air sucked into the combustion chamber of an engine at the specified cycle. Based on the present and the past sampled data, a forecasting means B forecasts the future physical quantity. Based on this forecasted future physical quantity, a fuel quantity computing means C computes the quantity of fuel which is to be supplied in the combustion chamber. Based on both the future physical quantity and the present sampled data taken at the point corresponding to that when this future physical quantity is forecasted, the shortage in quantity of fuel supplied in the combustion chamber is computed. The quantity of fuel computed by each of the computing means C and D is injected from a fuel injecting means E.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a fuel injection amount control device for an internal combustion engine, and in particular to a device for controlling the amount of fuel injection by predicting the amount of air taken into the combustion chamber of the engine. The present invention relates to an internal combustion engine Q fuel injection amount control device.

[Conventional technology]

Conventionally, the amount of air passing upstream of the throttle valve or the intake pipe absolute pressure (hereinafter referred to as intake pipe pressure) downstream of the throttle valve is sampled at a predetermined period, and based on this sampling value and the detected value of the engine rotation speed. Calculate the basic fuel injection time using A fuel injection amount control device for an internal combustion engine that controls the injection amount is known. The above-mentioned physical quantities of air amount and intake pipe pressure both correspond to the amount of air taken into the engine combustion chamber. In order to supply the amount of fuel required by the engine to the engine combustion chamber, it is necessary to sample physical quantities at the time when the amount of air taken into the engine combustion chamber is determined, that is, around the time when the intake valve is closed, including when the intake valve is closed. The fuel injection amount may be controlled using the value. However, a predetermined time is required to calculate the fuel injection time, a predetermined flight time is required for the fuel injected from the fuel injection valve to reach the combustion chamber, and the amount of air taken into the combustion chamber If the amount of fuel to be injected is calculated and injected when this is determined, the injected fuel will not be supplied to the engine combustion chamber due to the time delay.

For this reason, conventionally, the pressure in the intake pipe at the time when the injected fuel reaches the combustion chamber is predicted according to the following formula, which is determined by taking into account up to the second differential term of the macro-phosphorus expanded polynomial. , the fuel injection amount is calculated and injected using the predicted intake pipe internal pressure PMF (Japanese Patent Laid-Open Nos. 60-169647, 1982-1572).
Publication No. 44).

PMF=2.5PM-2,0PM360+0.5PM7
20 However, PM is the sampled current intake pipe pressure, P
M360 is the intake pipe pressure sampled 360'CA (crank angle) before the current time, PM720 is the intake pipe pressure sampled 360'CA (crank angle) before the current time.
This is the intake pipe pressure sampled before 0°CA.

However, with the above technology, if the period between the time to predict (predicted light) and the actual predicted time is long, the predicted value and the actual value may differ due to changes in operating conditions after predicting the intake pipe pressure, etc. For example, if you accelerate after predicting the intake pipe pressure, the amount of air actually taken into the combustion chamber will be larger than the predicted value, resulting in a lean air-fuel ratio, which will affect drivability and exhaust emissions. Getting worse. In order to solve this problem, conventionally, Japanese Patent Application Laid-Open No. 63-7532
As shown in Publication No. 5, in addition to the main fuel injection device, a direct fuel injection device that injects fuel directly into the cylinder is provided,
The fuel injection amount is calculated from the intake air amount detected by the air flow meter and the engine rotation speed detected by the crank angle sensor, and the shortfall in the fuel injection amount is determined, and fuel is injected from the main fuel injection device and the fuel injection amount is The shortage is directly injected into the cylinder from a direct fuel injection device.

[Problem to be solved by the invention]

However, in the above conventional technology, the fuel injection amount is calculated based on the detected intake air amount, so during sudden acceleration, the detected intake air amount when calculating the fuel injection amount is different from the intake air amount near the intake valve closing. The difference becomes larger, and as a result, there is a risk that the insufficient amount of fuel injection amount will increase and the entire amount of the insufficient amount cannot be injected before ignition. Furthermore, there is a problem in that a direct fuel injection device is required in addition to the main fuel injection device, which increases manufacturing costs.

The present invention has been made in order to solve the above-mentioned problems, without increasing the number of fuel injection valves normally provided in the engine, and by minimizing the amount of fuel injector that is insufficient in fuel supply during sudden acceleration, etc. An object of the present invention is to provide a fuel injection amount control device for an internal combustion engine that prevents deterioration of exhaust emissions.

[Means to solve the problem]

In order to achieve the above object, the present invention, as shown in FIG. a prediction means B for predicting the future physical quantity based on the sampled value; a fuel quantity calculation means C for calculating the quantity of fuel to be supplied to the engine combustion chamber based on the future physical quantity; a shortage calculation means for calculating a shortage of fuel to be supplied to the engine combustion chamber from a physical quantity and a current sampling value at a time corresponding to the future physical quantity; the fuel quantity calculation means C; and the shortage amount. The fuel injecting means E injects the amount of fuel calculated by the calculating means.

[Effect]

The present invention will be explained in detail below. The sampling means A is
Physical quantities related to the amount of air taken into the engine combustion chamber (for example, the amount of air passing upstream of the throttle valve, the intake pipe pressure downstream of the throttle valve, etc.) are sampled at predetermined intervals. Prediction means B predicts future physical quantities based on current sampling values and past sampling values. This future physical quantity is preferably the amount of air that exists in the engine combustion chamber when the intake valve is closed, that is, the amount of air that contributes to combustion. The predicted value of the physical quantity at a predetermined point in time up to (or around this point) is a value that poses no problem in practice. The fuel amount calculating means C calculates the amount of fuel to be supplied to the engine combustion chamber based on a future physical quantity (predicted value predicted by the predicting means B). In addition, the shortfall amount calculation means calculates the engine combustion chamber from the future physical quantity predicted by the prediction means B and the current sampling value at the time corresponding to this future physical quantity (sampling value near the intake valve closing). Calculate the amount of fuel shortage that should be supplied to the Then, the fuel injection means E injects the amount of fuel calculated by the fuel amount calculation means C and the shortage amount calculation means. In this way, since the prediction means B predicts a future physical quantity and injects the amount of fuel corresponding to the predicted value of this physical quantity, the difference between the predicted value and the actual sampling value corresponding to this predicted value is The difference can be minimized, thereby minimizing the amount of fuel shortage and supplying the entire amount of fuel shortage into the combustion chamber in a short period of time. Furthermore, since the fuel injection means E injects the amount of fuel to be supplied to the engine combustion chamber and the insufficient amount of fuel, there is no need to provide a new fuel injection means.

[Effects of the Invention] As explained above, according to the present invention, without increasing the number of fuel injection valves, the shortage of fuel injection amount is minimized, and exhaust emissions due to insufficient fuel supply amount during sudden acceleration etc. can be reduced. This has the effect of preventing the deterioration of

〔Example〕

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

In this embodiment, the present invention is applied to a four-cylinder engine so that fuel injection control is performed independently for the four cylinders. FIG. 2 schematically shows an internal combustion engine equipped with a fuel injection amount control device to which the present invention is applicable.

This engine is controlled by an electronic control circuit such as a microcomputer, and a throttle valve 8 is disposed downstream of an air cleaner (not shown). An idle switch 10 that is turned on is attached, and a surge tank 12 is provided downstream of the throttle valve 8. A semiconductor pressure sensor 6 is attached to this surge tank 12 . This pressure sensor 6 has a small time constant (for example, 3 to 5 m5ec) for removing the pulsating component of the intake pipe pressure.
) and is connected to a filter (FIG. 3) composed of a CR filter or the like with good response.

Note that this filter may be built into the pressure sensor. Additionally, the surge tank 12 bypasses the throttle valve 8 and is located on the upstream side of the throttle valve and the downstream side of the throttle valve.
A bypass path 14 is provided to communicate with the.

An ISC (idle speed control) pulp 16B whose opening degree is adjusted by a pulse motor 16A equipped with a four-pole stator is attached to this bypass path 14.

The surge tank 12 is communicated with the combustion chamber of the engine 20 via an intake manifold 18 and an intake boat 22. A fuel injection valve 24 is attached to each cylinder so as to protrude into the intake manifold 18.

The combustion chamber of the engine 20 is communicated via an exhaust boat 26 and an exhaust manifold 28 to a catalyst device (not shown) filled with a three-way catalyst. An 02 sensor 30 is attached to the exhaust manifold 28 and outputs a signal that is inverted from the stoichiometric air-fuel ratio. A cooling water temperature sensor 34 is attached to the engine block 32 so as to penetrate through the engine block 32 and protrude into the water jacket. This cooling water temperature sensor 34
detects the engine cooling water temperature and outputs a water temperature signal, which represents the engine temperature. Note that engine oil salt may be detected to represent the engine temperature.

A spark plug 38 is attached to each cylinder of the engine 20 so as to penetrate through the Rad 36 and protrude into the combustion chamber. This spark plug 3 is connected via a distributor 40 and an igniter 42 to an electronic control circuit 44 composed of a microcomputer or the like. Inside the distributor 40, a cylinder discrimination sensor 46 and a rotation angle sensor 48 are each constructed of a signal rotor fixed to the distributor shaft and a pickup fixed to the distributor housing.
is installed. The cylinder discrimination sensor 46 is, for example, 72
A cylinder discrimination signal is output every 0'CA, and the rotation angle sensor 48
outputs an engine rotation speed signal every 30° CA, for example.

As shown in FIG. 3, the electronic control circuit 44 includes a microprocessing unit (MPU) 60, a read-only
Memory (ROM) 62, random access memory (
RAM) 64, backup RAM (BU-RAM) 66
, input/output capotro 8, input port door 0, output port door 2
．． 74, 76, and a bus 75 such as a data bus or a control bus that connects them. An analog-to-digital (A/D) converter 78 and a multiplexer 80 are connected in sequence to the input/output capotro 8. The pressure sensor 6 is connected to the multiplexer 80 via a CR filter 7 and a buffer 82 which are composed of a resistor R and a capacitor C, and the cooling water temperature sensor 34 is also connected via a buffer 84 . Further, the idle switch 10 is connected to the multiplexer 80.

The MPU 60 controls the multiplexer 80 and the A/D converter 78 to sequentially convert the output of the pressure sensor 6, the output of the idle switch 10, and the output of the cooling water temperature sensor 34, which are input via the CR filter 7, into digital signals and send the signals to the RA.
Store it in M64.

This A/D conversion can be performed every 180° CA, but may also be performed every predetermined time. Therefore, multiplexer 80. The A/D converter 78, the MPU 60, and the like act as sampling means that samples the pressure sensor output at a predetermined crank angle (at a predetermined period). The input port door 0 is connected to the 02 sensor 30 via a comparator 88 and a buffer 86, and also has a waveform shaping circuit 9.
0, the cylinder discrimination sensor 46 and the rotation angle sensor 48
is connected. The output port door 2 is connected to the igniter 42 via a drive circuit 92, and the output port door 4 is connected to the fuel injection valve 2 via a drive circuit 94 equipped with a down counter.
4, and the output port door 6 is connected to the ISC valve pulse motor 16A via a drive circuit 96. Note that 9th is a clock and 99 is a timer. The ROM 62 stores in advance a control routine program, etc., which will be explained below.

Fig. 4 shows an asynchronous fuel injection execution routine that is executed every 180° CA.
The current sampling value PM of the intake pipe pressure stored in M is taken. In the next step 142, the fuel injection amount corresponding to the current sampling value PM, that is, the actual fuel injection time tTAU representing the actual fuel injection amount actually requested by the engine is calculated according to the following equation.

TAU=PM-KINJ-FWL...(1)
However, KINJ is a conversion coefficient for converting intake pipe pressure into fuel injection time, and FWL is a correction coefficient determined according to engine cooling water temperature. In the next step 144, the asynchronous fuel injection time TAUASY is calculated by subtracting the predicted fuel injection time TAUR (calculated in step 162 in FIG. 5) from the actual fuel injection time tTAU. In step 146, the minimum fuel injection time T determined by the asynchronous fuel injection time TAUASY and the characteristics of the fuel injection valve is determined.
AUMIN (the minimum amount of fuel that can be injected by the fuel injection valve) is compared, and if TAUASY>TAUMrN, fuel injection is immediately executed in step 148, thereby executing asynchronous fuel injection. And step 150
After calculating the predicted intake pipe pressure PMF in Step 1
After inverting the flag XTAUCAL in step 52, the process returns. Note that the calculation of the predicted intake pipe pressure PMF will be described later.

FIG. 5 shows the fuel injection time TAU calculation routine, and in step 160 it is determined whether the flag XTAUCAL has been reset.

When the flag XTAUCAL has been reset, the predicted fuel injection time TAUR is calculated in accordance with the following formula in step 162.

TAUR=PMF-K INJ-FWL・FAF・
(2) However, FAF is an air-fuel ratio feedback correction coefficient for feedback-controlling the air-fuel ratio to the stoichiometric air-fuel ratio based on the 0□ sensor output.

Here, since the flag XTAUCAL is inverted every 180° CA in step 152, the predicted fuel injection time TAUR is calculated every 360° CA. In step 164, the increase molecule AUW due to the amount of fuel adhering to the intake pipe wall surface (manifold wet amount) is calculated as follows (3
)2, and the fuel injection time TAU for actually opening the fuel injection valve in step 166 is calculated based on the following (4
) is calculated and stored in RAM. Note that details of the following equations (3) and (4) will be described later.

TAUW = 2 (TAUR-TAUi-.

10TAUIi) ...(3) TAU=TAUR+TAUW ...(
4) FIG. 6 shows the fuel injection routine, in which it is determined in step 170 whether or not it is the fuel injection timing, and when it is the fuel injection timing, the RA is activated in step 172.
The fuel injection time TAU stored in M is taken in, and in step 174, the fuel injection valve is opened for a time corresponding to the fuel injection time TAU to perform synchronous fuel injection. In addition,
When there is a request for asynchronous fuel injection during execution of synchronous fuel injection, the synchronous fuel injection time TAU is extended by a time corresponding to the asynchronous fuel injection time T AU 'ASy. FIG. 7 shows the timing of synchronous fuel injection and asynchronous fuel injection when controlled as described above.

The principle of calculating the predicted intake pipe pressure PMF will be explained below. X'
Let f (x) be the function indicating the intake pipe pressure at CA, then
' When the intake pipe pressure at the CA destination is to be predicted, the intake pipe pressure at the predicted destination is expressed by a function f (x+m). When this function is expanded by Taylor, the following equation (5) is obtained.

n! Here, r (x+m)EPMF is the current intake pipe pressure f(x) = PM, a' intake pipe pressure before CA, PMa, 2
a' If the intake pipe pressure before CA is expressed as PM2a, then a a PM'-PMa'["(x)=PM" dust □ Therefore, the above equation (5) can be changed to the following equation (8). become.

m m2 ・ΔΔPM+・・・・・・・(8) Above (8)
If the third term and subsequent terms on the right side of the equation (ΔΔPM and below) are approximated by k·ΔPM+ΔΔPM, where k is the adaptation constant determined by experiment, the following equation (9) is obtained.

PMF = PM+(-+k) ・ΔPM+Δ
ΔPM (9) The control device that controls the fuel injection amount based on intake pipe pressure and engine speed uses the value obtained by processing the pressure sensor output with a CR filter and digital soft filter as the sampling value. (9) above
The predicted intake pipe pressure PMF in the equation is delayed by the amount of processing in the filter. Therefore, it is necessary to correct the adaptation constant k in consideration of the delay caused by the filter. The time constant of the filter is T,
If the engine rotational speed is NE, it is necessary to correct T, N, and E/60000. Furthermore, it is necessary to adapt the predicted crank angle depending on the fuel injection method (simultaneous injection or independent injection). Therefore, a new adaptation constant that takes into consideration the correction of the delay of the filter and the crank angle of the prediction destination is set to kl, and since Equation (9) is modified by these, the following is obtained.

PMF=PM2 a ten (2+-10 k l) (PM-
PMa)=PM2a+ (2+-+kl) ΔPM
° ...(10) There is a relationship shown in Figure 8 between each term in 01) 2 above,
Since PM is included in the rate of change, when the sampling frequency is small and the intake pipe pressure changes and ΔPM increases, such as during low rotation or sudden acceleration, the predicted intake pipe pressure PMF
will overshoot. Also, undershooting occurs during sudden deceleration. Therefore, in this embodiment, as shown in FIG. 12, the ratio increases as the absolute value of the difference (rate of change) ΔPM between the current sampling value PM and the previous sampling value PMa increases. The predicted intake pipe pressure PMF is calculated using the following equation using a compression value DPM obtained by correcting the difference ΔPM and compressing the difference ΔPM so that the absolute value of the difference ΔPM becomes small.

PMF=PM2a+(2+-+k1)DPM
...G2) In the case of a 4-cylinder engine, there are cases in which fuel is injected into all four cylinders simultaneously once per engine revolution, and cases in which fuel is injected into all four cylinders independently. When fuel is injected at the timing shown in Figure (1), the cylinder that takes in the most amount of injected fuel is the first cylinder #l, and at this time, the amount of air taken into the combustion chamber of the first cylinder is It is determined by the intake pipe pressure when the cylinder's intake valve is closed.

Therefore, it is sufficient to predict the intake pipe pressure 360'CA ahead of the current time. Note that in the above, the predicted crank angle was determined based on the assumption that the largest amount of injected fuel is sucked into the first cylinder, but since it is also sucked into other cylinders, it is preferable to determine the predicted crank angle through experimentation. , in this case, as explained above, the adaptation constant is corrected by 1. 4
In the case of cylinder independent injection, as shown in Figure 9 (2), the fuel calculated at the current point in time and injected at the injection timing is sucked into the first cylinder #1, and at this time, the fuel is sucked into the engine combustion chamber. Since the amount of air to be used is determined by the intake pipe pressure when the intake valve of the first cylinder is closed, it is sufficient to predict the intake pipe pressure 360° CA ahead from the current time.

In addition, in the case of a 4-cylinder engine, the fluctuation period due to pulsation of intake pipe pressure is considered to be every 180'CA, so 180°CA
By sampling the intake pipe pressure every time, the influence of fluctuations due to pulsation can be minimized.

Therefore, in the case of a four-cylinder engine, it is sufficient to sample the intake pipe pressure every 180° CA and predict the intake pipe pressure 360° CA ahead from the current time. Therefore, in the case of a 4-cylinder engine, if a=180 and m=360, the predicted intake pipe pressure PMF
becomes as follows.

PMF=PM360+ (4+kl)DPM...
θ Also, in the case of a 6-cylinder engine, Fig. 10 (1), (
As can be understood from the fuel injection timing shown in 2), sampling is performed every 120° CA, and 360°
'The intake pipe pressure at the CA end can be predicted, so a=120. If m=360, predicted intake pipe pressure PM
F becomes as follows.

PMF=PM240+ (5+k 1) ・DPM
The same applies when the amount of air passing upstream of the throttle valve is used as the physical quantity related to the amount of air taken into the engine combustion chamber.

FIG. 11 shows the predicted intake pipe pressure PMF according to the above principle.
This shows a detailed routine of step 150 in FIG. 4 of this embodiment for calculating the current intake pipe pressure PM, the intake pipe pressure PM18 before 180° CA in step 100
0 and 360' Intake pipe pressure PM360 before CA
By fetching from AM, the current sampling value, the previous sampling value, and the sampling value from the time before the previous one are fetched.

In step 102, 180
By subtracting the intake pipe pressure PM180 before °CA, the rate of change ΔPM of the intake pipe pressure is calculated. Rate of change ΔPM
is positive when accelerating and qualitative when decelerating. In the next step 104, it is determined whether or not a transient state exists by determining whether the absolute value 1ΔPMI of the rate of change is greater than or equal to a predetermined value α. When it is determined that the state is in a transient state, in step 106, a compression value DPM corresponding to the change rate ΔPM is calculated from a table of change rate ΔPM and compression value DPM shown in FIG. This compressed value DPM is compressed so that its absolute value becomes smaller as the absolute value of the rate of change ΔPM becomes larger, and as a result, DPM=ΔP
It is a value obtained by logarithmically compressing the M curve. In addition, ΔPM
The degree of compression of ΔPM>O (during acceleration) and ΔP
It is not necessarily necessary to match the region where M<O (during deceleration), and it may be determined according to the characteristics of the engine.

In the next step 108, 1 is calculated as the adaptation constant corresponding to the current engine rotation speed NE from the table of adaptation constants kl determined according to the engine rotation speed NE shown in FIG. The adaptation constant multiplier kl is set to an initial value of 0 and is set to increase as the engine rotation speed increases. Note that 2+kl may be used as the adaptation constant. In step 11O, the predicted intake pipe pressure PMF is calculated according to the equation shown in equation 03) above, and in step 112 and step 114, the intake pipe pressure PM180 before 180'CA is calculated.
After replacing the current intake pipe pressure PM with the intake pipe pressure before 360° CA and replacing the current intake pipe pressure PM with the intake pipe pressure before 180° CA, the process proceeds to step 152.

On the other hand, in step 104, the absolute value of the rate of change is 1ΔPM.
When it is determined that I is less than the predetermined value α and the engine operating state is determined to be a steady operating state, the predicted intake pipe pressure PMF is calculated using the intake pipe pressure PM180 and the rate of change ΔPM according to the following formula, and step 120 and step 122
Intake pipe pressure PMI80 before 180'CA at 36
Intake pipe pressure before 0°CA, predicted intake pipe pressure PMF to 18
After replacing each with the intake pipe pressure before 0'CA, the process proceeds to step 152.

In step 122, the predicted intake pipe pressure PMF is replaced with the intake pipe pressure PM180 and the predicted intake pipe pressure PMF is calculated based on the above 0ω formula. When transformed, it becomes as shown in the following equation 06).

As can be understood from the above equation 00, the predicted intake pipe pressure PMF at steady state is calculated by adding a heavier weight to the previous predicted intake pipe pressure PMF0 to the current intake pipe pressure PM and the previous predicted intake pipe pressure P.
It is obtained by calculating the weighted average value of MF. Such a weighted average value can be obtained by digital filtering processing.

Next, the above equations (3) and (4) will be explained in detail.

α of the fuel injection amount TAUO to be injected this time is deposited on the wall surface, TAU・(1−α) is inhaled by the engine, β of the amount Q of fuel deposited on the wall surface remains on the wall surface, and Q・(1−β) is the engine Assuming that it is inhaled, the adhesion IQi and the inhalation amount F are as follows.

Adhesion amount Qi = α・TAU+β・Q, -1...07
) Suction amount F=TAU・(1−α) +Q=−+・(1−β) ...0ω The suction amount F taken into the engine is TP −FWL・FAF・・・・=
Since it is sufficient to determine TAU so that it is equal to TAUR, 00 becomes as follows.

Fi =TAUR=TAU・(1-α)+Q=-+
・ (1-β) ...Q9) Solving for TAU, T AU = (T AU RQ = -+
・ (1-β))■-α...+2al From formula 07), Qi-1=α・TA(J, −, +β・Q
Since i −z, TAU=-(TAUR-α・T AU, −Il−α −β・Q, −2+β・Q direct −I) ...(21) ...(22) .

Here, if TALIW=TAU-TAUR and the amount of increase due to manifold wet is assumed, the increase molecule AUW will be as follows.

TA[JW=TAU-TAIJR =-(TAU R-α・TAU,-.

1−α +β・(Ql−+ −Qt−z ))−TAuR
+α・TAUR−α・TAU, −.

+β・ (Qi−, −Q=2 )) ;□(α・ (TAUR−TA, Ui−1)1−α +β・ (Qi−, −Q, −2>) ・・・(23) Here Considering the second term of equation (23), Q i−
I Qi-2=α・(T A U r-1T A
U r-z ) + β・ (Qi-, -Qi,, 3) β・ (Qt-z-Qi-3) = α・β・ (TAUi-+ TAUt-z )
+α・β2 ・ (TAUi-z TAU=-:+
)+α゛β3 ・('rAu, -, -TAUi,
, 4) Substituting this into equation (23), 1-α + α・Σ βj ・ΔTAU=,) =−((TAUR−TAUi−,) 1−α +Σ βJ ・ΔTAUi−,) ・・・(25 ) AU, -4=TAU IL, TAU 1. −,=TAU
When Oi is assumed, equation (25) becomes the following.

TAUW=2 ・ ((TAUR-TALIi-,
)+TAUIi l...(26)TA
UIi-to 3・I (TAUi-, -TAU
Oi ) + TA U r r-1) ... (2
7) T A U OH= T A U I l-z
...(28) K3=β
(30) Therefore, the TAU to be injected is the sum of the TAUR to be inhaled into the engine combustion chamber and the wet molecules ATJW attached to the manifold, as shown in equation (31).

TAU=TAUR+TAUW (31) Next, another embodiment of the present invention will be described. In this example,
This is to deal with cases where the change in intake pipe pressure at 180° CA is extremely large, such as in full-throttle racing.

FIG. 14 shows a routine that is executed every predetermined time (for example, 4m5ec), and in step 180, A
/D conversion is started, and the A/D conversion value of the pressure sensor output is stored in the RAM as the current sampling value PM of the intake pipe pressure (step 182). In the next step 184,
The rate of change ΔPM is calculated by subtracting the value stored in the register PMINJ from the current sampling value PM, and it is determined in step 186 whether the rate of change ΔPM is greater than or equal to a predetermined value A. When ΔPM≧A, the current sampling value PM is stored in the register P in step 188.
After calculating the asynchronous fuel injection time TAUASY according to the following formula in step 190, asynchronous 3Ul fuel injection is executed in step 192.

TAUASY=ΔPM・KINJ・ (1+FWL+FASE)...(32) Figure 15 is 3
This routine is executed every 60° CA to calculate the predicted intake pipe pressure PMF. In step 150, the predicted intake pipe pressure PMF is calculated as described above, and in step 196, the predicted intake pipe pressure PMF is calculated according to the following equation (32). After calculating the fuel injection time TAU using the pipe pressure PMF, the predicted intake pipe pressure PMF is stored in the register PMINJ in step 198.

TAU=PMF-KINJ-FEV・FAF・(1+F
WL+FASE) (33) FIG. 16 shows the execution timing of asynchronous fuel injection when controlled as described above. As mentioned above, after the predicted intake pipe pressure PMF is stored in the register PMINJ, the current sampling value is stored in the register PMINJ every time A/D conversion is activated, so that the predicted intake pipe pressure and the current sampling value are stored in the register PMINJ. The first asynchronous fuel injection is performed when the difference from the sampled value is greater than or equal to a predetermined value A, and thereafter, an asynchronous fuel injection is performed each time the rate of change in the sampling value, that is, the rate of change in the intake pipe pressure exceeds a predetermined value. . Therefore, the shortfall in the A/D conversion example fuel injection amount is determined and asynchronous fuel injection is executed.
It is possible to bring the fuel injection amount closer to the value required by the engine.

[Brief explanation of the drawing]

FIG. 1 is a block diagram corresponding to the claims of the present invention, FIG. 2 is a schematic diagram of an internal combustion engine equipped with a fuel injection amount control device to which the present invention can be applied, and FIG. 3 is a control diagram of FIG. A block diagram showing details of the circuit, FIG. 4 is a flowchart showing an asynchronous fuel injection routine in an embodiment of the present invention, FIG. 5 is a flowchart showing a fuel injection time calculation routine in the above embodiment, and FIG. 6 is a flowchart showing the above embodiment. 7 is a flow chart showing the timing of asynchronous fuel injection and synchronous fuel injection in the above embodiment, and FIG. 8 is a flow chart showing the timing of the asynchronous fuel injection and synchronous fuel injection in the above embodiment. Fig. 9 (1) and (2) are diagrams for explaining the injection timing of a four-cylinder engine; Figures (1) and (2) are diagrams for explaining the injection timing of a six-cylinder engine, Figure 11 is a flowchart showing details of step 150, Figure 12 is a diagram showing a table of compression values DPM, Figure 13 is a diagram showing changes in the adaptation constant Kl, the first
FIG. 4 is a flowchart showing an asynchronous fuel injection routine in another embodiment of the present invention, FIG. 15 is a flowchart showing a predicted intake pipe pressure calculation routine in the above embodiment, and FIG. 16 is a flowchart showing an asynchronous fuel injection routine in the above other embodiment. FIG. 3 is a diagram showing timing.

Claims (1)

[Claims] (1) sampling means for sampling a physical quantity related to the amount of air taken into the engine combustion chamber at a predetermined period; a prediction means for predicting the physical quantity in the future based on current sampling values and past sampling values; a fuel amount calculation means for calculating the amount of fuel to be supplied to the engine combustion chamber based on the future physical quantity; Fuel injection for an internal combustion engine, comprising: a shortage calculation means for calculating a shortage in the amount of fuel to be supplied; and a fuel injection means for injecting the amount of fuel calculated by the fuel amount calculation means and the shortage calculation means. Volume control device.