JP2677425B2 - Fuel injection amount control method for internal combustion engine - Google Patents

Description

[Detailed Description of the Invention] [Outline] Fuel injection amount of an internal combustion engine in which a fuel injection valve is provided corresponding to each of all combustion chambers, and the fuel injection valve simultaneously injects fuel for each revolution of the internal combustion engine. In the control method, the basic injection amount is obtained based on the intake pipe pressure at a predetermined calculation timing, and the first state amount related to the air flow rate passing through the throttle valve is obtained based on the opening of the throttle valve,
The second state quantity that changes following the first state quantity with a time delay and is related to the flow rate of the air supplied to the internal combustion engine is obtained.
The third state quantity related to the temporal change rate of the intake pipe pressure is obtained from the difference between the first state quantity and the second state quantity, and the time Δt1 from the fuel injection amount calculation timing to the intake valve closing timing and the intake pressure Filtering time of detector output Δt2
Of the processing delay correction value related to the sum of the above and the third state quantity, and the transient correction value decreases from the initial state of the transient state to the final stage of the transient state from the changing state of the third state quantity. By obtaining the transient correction amount based on the value and obtaining the fuel injection amount from the basic injection amount, the processing delay correction amount, and the transient correction amount, it is possible to realize the fuel injection amount control with high responsiveness and high accuracy. To do.

TECHNICAL FIELD The present invention relates to a fuel injection amount control method for controlling a fuel injection amount of an internal combustion engine, and more particularly to a fuel injection amount control method of a simultaneous injection method.

2. Description of the Related Art In a so-called electronically controlled fuel injection device, the simultaneous injection control is conventionally used to simplify a fuel injection valve drive circuit. On the other hand, a method of widely determining the fuel injection amount based on, for example, the intake pipe pressure and the rotation speed of the internal combustion engine, or based on the intake pipe pressure and the throttle valve opening degree is widely used.

The method using the intake pipe pressure and the throttle valve opening has relatively good responsiveness, but cannot accurately detect the mass flow rate of the intake air, so that there is an error due to altitude or temperature. May occur. In order to solve this problem, for example, an atmospheric pressure sensor or the like may be provided on the upstream side of the throttle valve to accurately detect the mass flow rate of the intake air. The cost increases because of the atmospheric pressure sensor added to.

Further, the method using the intake pipe pressure and the rotation speed is low in cost, but has a problem of poor responsiveness. That is, this is because the fluctuation range of the intake pressure due to opening and closing of the intake valve is
For example, since it reaches 50 to 100 mmHg at about 4000 rpm, the delay due to the filter processing performed to absorb such fluctuations is the main factor.

On the other hand, in the simultaneous injection control, as shown in FIG. 13 (2), the injection is performed every one revolution of the internal combustion engine, that is, every 360 degree crank angle (hereinafter referred to as “° C. A”). Therefore, among a plurality of combustion chambers, in a certain combustion chamber, the injection amount F1 + F2, F3 + F4,
F5 + F6, ... Inhaled. On the other hand, in the combustion chamber whose phase is different from this combustion chamber by 360 ° C,
By opening and closing the intake valve shown in Fig. (4), the injection amount F0 +
F1, F2 + F3, F4 + F5, ... are inhaled. That is, the injection is performed twice per stroke.

Therefore, during the transition in which the throttle valve opening is sharply opened as shown in FIG. 13 (1), it is necessary to correct the current injection amount based on the previous injection amount. However, if excessive correction is made, for example, the injection amount F1
On the other hand, when the transient correction is performed and the injection amount F2 becomes too large, so-called hunting occurs, such as reducing the injection amount F3 again, and the control becomes unstable. Further, in order to solve this, complicated arithmetic processing is required.

An object of the present invention is to provide a fuel injection amount control method for an internal combustion engine, which can perform simultaneous injection control stably and highly accurately and can improve transient response.

Means for Solving the Problems The present invention provides a fuel for an internal combustion engine in which a fuel injection valve is provided corresponding to each of all combustion chambers, and the fuel injection valve simultaneously injects fuel for each revolution of the internal combustion engine. In the injection amount control method, the basic injection amount is obtained based on the intake pipe pressure at a predetermined calculation timing, and the first state amount related to the air flow rate passing through the throttle valve is obtained based on the opening of the throttle valve, The second state quantity related to the flow rate of the air supplied to the internal combustion engine is determined by following the first state quantity with a time delay, and the intake pipe pressure is calculated from the difference between the first state quantity and the second state quantity. Of the third state quantity related to the time change rate of the fuel injection amount, and the processing delay correction related to the sum of the time Δt1 from the fuel injection amount calculation timing to the intake valve closing timing and the filtering processing time Δt2 of the output of the intake pressure detector Value and before The processing delay correction amount is obtained from the third state amount, and the transient correction amount is obtained from the change state of the third state amount based on the transient correction value that decreases from the initial stage of the transient period to the final stage of the transient period. A fuel injection amount control method for an internal combustion engine, characterized in that a fuel injection amount is obtained from an injection amount, the processing delay correction amount, and the transient correction amount.

Further, the present invention is a fuel injection amount control method for an internal combustion engine, wherein a fuel injection valve is provided corresponding to each of all combustion chambers, and the fuel injection valve simultaneously injects fuel for each revolution of the internal combustion engine. Based on the opening of the throttle valve, a first state quantity related to the air flow rate passing through the throttle valve is obtained, and the first state quantity is tracked and changed with a time delay, and the air flow rate supplied to the internal combustion engine. Is calculated from the difference between the first state quantity and the second state quantity, and the third state quantity is calculated from the difference between the first state quantity and the second state quantity, and the intake valve is calculated from the fuel injection amount calculation timing. The processing delay correction value related to the sum of the time Δt1 until the closing timing and the filter processing time Δt2 of the output of the intake pressure detector and the third state quantity are used to obtain the processing delay correction pressure. From change state to transition The transient correction pressure is obtained based on the transient correction value that decreases from the initial stage toward the end of the transient time, and the fuel injection amount is obtained using the intake pipe pressure at the calculation timing, the processing delay correction pressure, and the transient correction pressure. A fuel injection amount control method for an internal combustion engine, comprising:

Operation According to the present invention, the first based on the opening of the throttle valve
State quantity is required. The obtained first state quantity is related to the air flow rate passing through the throttle valve, and follows the transient state of the throttle valve opening / closing operation with good responsiveness. The second state quantity related to the intake air flow rate supplied to the internal combustion engine changes following the first state quantity with a time delay. The third state quantity is obtained from the difference between the first state quantity and the second state quantity. This third state quantity is related to the time change rate of the intake pipe pressure and has a predetermined relationship with this time change rate. Therefore,
The processing delay correction amount related to the sum of the time Δt1 from the fuel injection amount calculation timing to the intake valve closing timing and the filter processing time Δt2 of the output of the intake pressure detector, and the processing delay correction amount based on the third state amount. Is required. Further, the transient correction amount is obtained from the change state of the third state quantity based on the transient correction value that decreases from the initial stage of the transient period to the final stage of the transient period. In this way, the transient correction can be smoothed by increasing the transient correction value in the early stage of the transient time and decreasing the transient correction value in the final stage of the transient time. Then, the fuel injection amount is obtained from the basic injection amount obtained based on the intake pipe pressure, the processing delay correction amount, and the transient correction amount, and the fuel injection amount obtained in this way is optimal for the internal combustion engine. It becomes the fuel supply amount.

Further, instead of obtaining the correction amount for correcting the basic injection amount, in other words, the processing delay correction amount and the transient correction amount, the processing delay correction pressure and the transient correction pressure for correcting the intake pipe pressure are obtained. You can also do it. That is, a processing delay correction value related to the sum of the time Δt1 from the fuel injection amount calculation timing to the intake valve closing timing and the filter processing time Δt2 of the output of the intake pressure detector, and the processing delay due to the third state quantity. Corrected pressure is required. Further, from the changing state of the third state quantity, the transient correction pressure is obtained based on the transient correction value that decreases from the initial stage of the transient period to the final stage of the transient period. Then, the fuel injection amount is obtained from the intake pipe pressure at the calculation timing, the processing delay correction pressure, and the transient correction pressure. The fuel injection amount determined in this way is the optimum fuel supply to the internal combustion engine. It becomes the amount.

Embodiment FIG. 1 is a control apparatus 1 for an internal combustion engine according to an embodiment of the present invention.
FIG. 3 is a block diagram showing a configuration related to the above. A plurality of combustion chambers E1 to Em are formed in the internal combustion engine 10, and combustion air introduced from the intake port 2 is introduced into these combustion chambers E1 to Em.
After being purified by the air cleaner 3, it is supplied from the intake pipe 4 through the surge tank 6 and the intake pipe 7. The intake pipe 4 is provided with a throttle valve 5 for adjusting the inflow amount of the combustion air.
Is interposed. Combustion air from the surge tank 6 through the intake pipe 7 is guided to intake pipe lines A1 to Am individually provided for the combustion chambers E1 to Em, respectively. Fuel injection valves B1 to Bm are provided in the intake pipe lines A1 to Am, respectively. Each combustion chamber E1
-Em are provided with intake valves C1-Cm and exhaust valves D1-Dm, respectively. The internal combustion engine 10 has, for example, spark plugs G1 to Gm.
And a four-cycle spark ignition internal combustion engine. Each fuel chamber
The exhaust gas from E1 to Em is discharged from the exhaust pipe 14 through the three-way catalyst 15 into the atmosphere.

The intake pipe 4 is provided with an intake air temperature detector 21 for detecting the temperature of intake air, a throttle valve opening detector 22 is provided in association with the throttle valve 5, and the surge tank 6 is provided with an intake pipe 7 An intake pressure detector 23 for detecting pressure is provided. A cooling water temperature detector 24 is provided near the combustion chambers E1 to Em.
In the exhaust pipe 14, an oxygen concentration detector 25 is provided upstream of the three-way catalyst 15, and an exhaust temperature detector 26 is provided downstream of the three-way catalyst 15. The rotation speed of the internal combustion engine 10, that is, the number of rotations per unit time, is detected by a crank angle detector 27.

The control device 1 includes a vehicle speed detector 28 and a starter motor 33 for starting the internal combustion engine 10 together with the detectors 21 to 27.
Start detector 29 to detect if is activated
When an automobile equipped with the internal combustion engine 10 is equipped with an automatic transmission, an air-conditioning detector 30 for detecting the use of an air conditioner, etc., and whether the shift stage of the automatic transmission is in the neutral position or not. The detection result from the neutral detector 31 for detecting is input.

Further, the control device 1 is energized by a battery 34, and the control device 1 includes the detectors 21 to 31.
Based on the detection result of, and the power supply voltage of the battery 34 detected by the voltage detector 20, the fuel injection amount, the ignition timing, etc. are calculated, and the fuel injection valves B1 to Bm and the spark plugs G1 to Gm, etc. To control. The control device 1 also drives the fuel pump 32 when the internal combustion engine 10 is operating.

FIG. 2 is a block diagram showing a specific configuration of the control device 1. The detection results of the detectors 20 to 25 are supplied from an input interface circuit 41 to a processing circuit 43 via an analog / digital converter 42. In addition, the detector 22, 27-3
The detection result of 1 is given to the processing circuit 43 via the input interface circuit 44. The processing circuit 43 is provided with a memory 45 for storing various control maps and learning values.The processing circuit 43 receives power from the battery 34 through a constant voltage circuit 46. Supplied via

The control output from the processing circuit 43 is derived via the output interface circuit 47, is given to the fuel injection valves B1 to Bm to control the fuel injection amount, and is given to the ignition plugs G1 to Gm to set the ignition timing. Is controlled and also fuel pump 32
Is driven.

The detection result of the exhaust gas temperature detector 26 is given to an exhaust gas temperature detection circuit 49 in the control device 1. When the detection result is abnormally high, the warning lamp 51 is turned on via the drive circuit 50.

In the control device 1 configured as described above, the detection output of the intake pressure detector 23 used for calculating the fuel injection amount and the ignition timing includes the intake valve 9 as shown in FIG.
, And the fluctuation range is a large value of, for example, about 50 to 100 mmHg at 4000 rpm as described above. In order to absorb this fluctuation and detect an accurate intake pipe pressure, the detection output of the intake pressure detector 23 is filtered in the control device 1.

Therefore, even if the throttle valve 5 is rapidly opened as shown in FIG. 3 (2) due to the delay caused by the filtering, the pressure waveform after the filtering is, for example,
In FIG. 3 (3), with respect to the change of the pressure waveform of the actual intake pressure indicated by the reference numeral l1, the reference numeral l2 is delayed by Δt2.
Appears as indicated by.

The amount of fuel injected from the fuel injection valves B1 to Bm needs to be an amount commensurate with the amount of air taken into the combustion chamber 11 at the end of the intake stroke. That is, it is necessary to calculate the injection amount based on the intake pipe pressure immediately before the intake valve 9 is closed. In practice, the intake valve 9 is, for example, as shown in FIG.
It started to open from before, and it will be closed when the bottom dead center is 46 ℃. Therefore, in consideration of the injection amount calculation time shown in FIG. 3 (5), as shown in FIG. 3 (6), the intake pipe pressure reading and the injection amount calculation timing t1 are, for example, It is said to be 90 ° C before the dead point.

Therefore, in FIG. 3 (3), when the injection amount is calculated based on the intake pipe pressure at the calculation timing t1, the actual intake pipe at the timing t2 at which the intake valve 9 that should originally be used for the calculation of the injection amount is closed. The pressure is reduced by a pressure difference ΔP1 corresponding to the time difference Δt1 and a pressure difference ΔP2 corresponding to the filter processing time Δt2, resulting in lean combustion. Therefore, it is necessary to predict and obtain the pressure difference ΔP1 + ΔP2 corresponding to the delay of time Δt1 + Δt2, and correct the intake pipe pressure at the calculation timing t1.

As shown in FIG. 3 (3), the pressure waveform l2 after the filter processing is substantially equal to the pressure waveform l1 of the actual intake pressure, and therefore, the time change rate dP / dt of the intake pressure P is accurately obtained. This makes it possible to accurately correct such a delay.

The time rate of change dP / dt is determined as follows. That is, through the throttle valve 5, the surge tank 6
Qin of the intake air flow rate (related to the first state quantity) flowing to
When Qout is the flow rate of outflow air from the surge tank 6, in other words, the flow rate of air supplied to the internal combustion engine 10 (related to the second state quantity), the first value related to the time change rate dp / dt of the intake pressure The variation K1 · dp / dt related to the three state quantities is Becomes However, ΔQ is the amount of change in the intake air flow rate,
K1 is a constant. Further, the opening of the throttle valve 5 is θ,
If the rotation speed of the internal combustion engine 10 is N, Qout = K3 · η · N · P (3) where K2 and K3 are constants, η is the intake efficiency, P
₀ is atmospheric pressure. Accordingly, from the first equation, the intake pressure P for which the delay correction has been performed is: However, Pi is the intake pressure at the calculation timing,
K1a = 1 / K1.

On the other hand, the time Δt1 according to the calculation timing is constant when viewed on the crank angle axis, and when the time between 180 ° C and A is T, Becomes In this formula 5, Δt1 / T is a constant value, which is set as A, and Δt2 is constant with respect to the time axis.
If this is B, Note that N = 1 / T, so that However, K1b = K1a · A.

Considering B / A here, the time required from the calculation timing to the timing t2 at which the intake valves C1 to Cm are closed is, for example, 316 ° C. Therefore, if the delay time due to the filter processing is, for example, 10 msec, Becomes Hereinafter, for simplification of description, this B / A will be described using the value of the eighth equation. Therefore, the seventh equation can be expressed as the ninth equation.

That is, regarding the calculation timing and the delay due to the filtering process, by accurately obtaining ΔQ, these corrections can be obtained with generality and high accuracy. The characteristic of the correction is proportional to the change in the air flow rate per unit rotation, and the influence of the filter processing is greatly corrected with the rotation speed.

Next, a method of calculating ΔQ / N will be described. The change in the intake air flow rate Qin when the throttle valve 5 is suddenly opened is
In FIG. 4, this is indicated by reference numeral l3. On the other hand, due to the influence of the surge tank 6, the outflow air flow rate Qout from the surge tank 6 is indicated by reference numeral 14. These flow rates Qin and Qout are expressed by the above-described second and third equations, respectively.

During steady operation of the internal combustion engine 10, Qin = Qout, and the flow rate Q
In is obtained in advance by actually measuring the flow rate Qout in a steady state using the throttle valve opening θ and the intake pressure P as parameters.
That is, the value corresponding to N · P in the third equation is
As shown in FIG. 5, it is assumed that the product value MAP of N and P at each throttle valve opening when the intake pressure P that keeps the throttle valve opening θ constant is changed. as a result,
The flow rate Qin can be expressed as in Expression 10. The graph shown in FIG. 5 is stored in the memory 45 as a map.

Qin = K3 · η · MAP… (10) Therefore, It can be expressed as.

However, in the eleventh equation, the MAP / N and P _M is
Manufacturing variations and of the internal combustion engine 10, the actual During controlled One by the secular change, and may not match in the steady state, Therefore, in this embodiment, the value Pc obtained connexion by the intake pressure P _M in the calculation Replace with Be the intake air pressure P _M is deviation occurs due to the variation as described above, the time rate of change dP / dt is substantially identical, the but similarly to the above-mentioned delay correction represented by connexion fourth equation, It can be expressed as. However, Pci is the current calculated value, and Pci _-1 is the previous calculated value. Therefore, MAP / N
(Corresponding to the first state quantity in this embodiment) and the calculated value Pc (corresponding to the second state quantity in this embodiment) always match in the steady state, and the throttle valve opening θ in the transient state. MAP / N changes abruptly with the change of, and the value Pc changes following to match it. Therefore, the 9th
From the equation, the eleventh equation, and the twelfth equation, it is possible to obtain the arithmetic expression regarding the delay correction shown in the thirteenth equation.

Here, K4 = K1b · K3 · η. Furthermore, the value Pc is the first
Based on the four formulas, for example, the approximation calculation is performed every 4 msec.

However, K5 = K1 · K3 · η.

Further, correction in a transient state such as when the throttle valve 5 is suddenly opened will be described with reference to FIG. The calculation of the fuel injection amount is performed, for example, every 360 ° C. A, and the fuel injection valves B1 to Bm are driven all together at each calculation. Therefore, as shown in Fig. 13 (3), the injection amount F1 + F2, F3 + F4, ..., Fm _-1 + Fm is sucked into a certain combustion chamber, and it is in phase with the combustion chamber by 360 ° C. In different combustion chambers, as shown in FIG. 13 (4), the injection amounts F0 + F1, F2 + F3, ..., Fm
_-2 + Fm _-1 is inhaled.

Therefore, when the throttle valve 5 is suddenly opened and the intake pressure rises as shown in FIG. 6 (1),
As shown in FIG. 6 (2), the reference marks ti, ti _-1, intake pressure Pi in the calculation timing indicated ... In, Pi _-1, ... and the time rate of change .DELTA.Pi at that timing, .DELTA.Pi _-1, ... If the correction is performed on the basis of the above, there is a possibility that hunting as described in the section of the related art may occur. For this reason, in the present embodiment, Pi, Pi _-1 is the target of the correction amount, and the total amount, namely 1.0, acts in the initial stage of the transient state, the amount corresponding to the change in the middle, for example, 0.5, and almost zero acts in the final stage. In addition, a transient correction value whose value decreases from the beginning of the transient time to the end of the transient time is used, and the transient correction amount is calculated based on the equation (15) using this transient correction value.

Further, if the rotation speed N is constant, it can be expressed as in Expression 16, and thus transient correction for simultaneous injection can be performed.

7 to 10 are flow charts for explaining the operations of the approximate calculation and the fuel injection amount calculation as described above. FIG. 7 shows the operation for obtaining the rotational speed NE of the internal combustion engine 10, and the measured value measured by the crank angle detector 27 is read in step s1. This behavior is, for example, 18
It is performed every 0 ° C.

FIG. 8 shows an operation for obtaining the intake pressure P _M, and the measurement result of the intake pressure detector 23 is digitally converted by the analog / digital converter 42 in step s11 and read into the processing circuit 43. This operation is performed, for example, every time a conversion operation is performed every 2 msec.

FIG. 9 is a flow chart for explaining the operation of the above-mentioned approximate calculation. For example, the analog / digital conversion operation of the slot valve opening θ detected by the slot valve opening detector 22 is performed every 4 msec. It happens every time. At step s21, the throttle valve opening θ is read, and step s
At 22, the map value MAP is read out from the throttle valve opening θ obtained at step s21 and the value Pc obtained at step s32 described later based on the graph shown in FIG.

In step s23, the value MAP is divided by the rotational speed NE to obtain the first state quantity. At step s24, the value Pc which is the second state quantity is subtracted from the result of the division. In step s25, the sign for the approximation calculation of the value Pc in step s32 described later is set according to whether the result of the subtraction in step s24 is positive or negative. In step s26, it is judged whether or not the set sign is positive. If not, the step s26 is executed.
After the absolute value of the subtraction result in step s24 is calculated in s27, the process proceeds to step s28, and if so, the process directly proceeds to step s28.

At step s28, the third state quantity which is the calculation result at step s24 or s27 is stored as the state quantity DPDT. In step s29, the above steps s24 or s2
The subtraction result in 7 and the rotation speed NE are multiplied. At step s30, the coefficient K5a is read from the map shown in FIG. 11 based on the detection result of the cooling water temperature detector 24. Although K5 = K1 · K3 · η (constant) in the above formula 14, this coefficient K5 is assumed to be a value K5a that changes depending on the cooling water temperature. This is because the value Pc is M at low temperature.
By slowing down the speed that follows the AP / N value, the corrected injection amount described later is made to act larger and longer than room temperature, and to cope with the shortage of the correction amount due to the adherence of fuel to the pipe wall. Is.

In step s31, the coefficient K5a is multiplied by the calculation result obtained in step s29, and the value Pc is updated in step s32 based on the code set in step s25 using this multiplication result. In this way,
The approximation calculation of the value Pc represented by the above-described fourteenth equation is performed.

FIG. 10 shows the operation for obtaining the actual fuel injection amount TAU, which is performed, for example, at every 360 ° C. At step s41, the basic injection amount TP is read from the rotational speed NE obtained at step s1 and the intake pressure P _M obtained at step s11. At step s42, a part of the calculation in the equation (13) is performed using the rotation speed NE. At step s43, the other part of the equation (13) is calculated from the rotational speed NE and the values MAP and Pc. Step s4
In 4, the operation results of steps s42 and s43 and the constant K4
Is multiplied by a conversion constant K6 to convert the fuel injection amount to include the corrected injection amount TM1 for the delay correction.

In step s45, the current state quantity DPDT and the previous state quantity DPD
The sum with PO is obtained, and the state quantity DPDT is divided by this sum at step s46 to obtain the transient correction value k. This transient correction value k is obtained in step s47 by the injection amount TP corresponding to Pi-Pi _-1 which is the target of the correction amount in the 15th and 16th equations.
It is multiplied by −TPO to obtain the corrected injection amount TM2 for the transient correction.

In step s48, the injection amount TP is updated by substituting the injection amount TPO, and in step s49, the state amount DPDTO is added to the state amount DP
DT is substituted and updated. At step s50, the actual fuel injection amount TAU is calculated from the basic injection amount TP obtained at step s41, the corrected injection amount TM1 obtained at step s44, and the corrected injection amount TM2 obtained at step s47. To be done.

In this way, the response delay due to the delay time Δt1 due to the calculation timing and the delay time Δt2 due to the filter processing, as shown in FIGS. 3 and 4, is absorbed by the detected output after the delay. Based on the time change rate dP / dt (∝MAP / N-Pc) of the actual detection output of the atmospheric pressure detector 23,
Since the correction is made as shown in the above equation 13,
In FIG. 3 (1), for example, even when the previous calculation timing is indicated by reference symbol A and the current calculation timing is indicated by reference symbol B, there is no influence of intake pressure fluctuation. With steady stability and high accuracy, even when the throttle valve 5 is suddenly opened and closed,
Good response can be followed from the beginning of the transient state.

Further, as shown in the sixteenth equation, since the correction according to the transient state is performed, the smooth correction can be performed and the hunting as described in the section of the prior art can be prevented. Furthermore, since the correction uses a relatively versatile arithmetic expression, it can be commonly used for internal combustion engines of different types.

In the above-mentioned embodiment, the basic injection amount TP and the corrected injection amount TM
Although the actual fuel injection amount TAU is obtained from 1 and TM2, as another embodiment of the present invention, based on the intake pressure P after the correction calculation and the rotation speed NE of the internal combustion engine 10 shown in the equation (16). hand,
The actual fuel injection amount TAU may be obtained directly.

The processing in this case is shown in FIG. This process is also the 10th
Similar to the figure, it is executed every 360 ° C. First step s51
Then, using the rotational speed NE obtained in step s1, a part of the calculation in the equation 13 is performed, and the calculation result is stored in the register L1. Then step s52
Then, from the rotational speed NE and the values MAP and Pc, the other part of the equation 13 is calculated, and the calculation result is stored in the register L2.

At step s53, the processing delay correction pressure P _MC is obtained based on the constant K4 and the values of the registers L1 and L2. In step s54, the processing delay correction pressure P _MC is used to obtain the pressure Pi obtained by correcting the actual measurement value P _M obtained in step s11. At step s55, the previous pressure Pi ₋₁ is subtracted from this pressure Pi and stored in the register L3. Step
At s56, the current pressure Pi is substituted for the previous pressure Pi _-1 and updated.

In steps s57, s58, s59, the steps s46, s47, s49
The same process is performed, and using the transient correction value k thus obtained, in step s60, the stored contents of the register L3 is corrected according to the sixteenth equation to obtain the transient correction pressure. As can be easily understood, the corrected intake pressure P is obtained from the intake pipe pressure at the calculation timing, the processing delay correction pressure, and the transient correction pressure.
And the rotational speed NE, the fuel injection amount TAU is obtained in step s61.
Is calculated.

Effect of the Invention As described above, according to the fuel injection amount control method of the first aspect of the present invention, the first state amount is obtained based on the opening degree of the throttle valve. The obtained first state quantity is related to the air flow rate passing through the throttle valve, and follows the transient state of the throttle valve opening / closing operation with good responsiveness. The second state quantity related to the intake air flow rate supplied to the internal combustion engine changes following the first state quantity with a time delay. The third state quantity is
It is obtained from the difference between the first state quantity and the second state quantity. This third state quantity is related to the time change rate of the intake pipe pressure and has a predetermined relationship with this time change rate. This third state quantity and the processing delay correction value related to the sum of the time Δt1 from the fuel injection amount calculation timing to the intake valve closing timing and the filter processing time Δt2 of the output of the intake pressure detector are related to the processing delay correction amount. Therefore, it is possible to accurately obtain the correction amount of the fuel even during the transient period when the throttle valve is rapidly opened and closed. In addition, since the transient correction amount is obtained from the change state of the third state quantity based on the transient correction value that decreases from the initial stage of the transient period to the final stage of the transient period, the transient correction value is increased in the initial stage of the transient period. , By reducing the transient correction value at the end of the transient period, the transient correction can be made smoother, and thus the transient correction amount is increased at the initial stage of the transient period, in other words, the fuel injection amount is increased, and the transient correction is performed at the end of the transient period. The correction amount can be reduced to prevent the correction hunting peculiar to the simultaneous injection method. Further, since the processing delay correction amount is obtained in consideration of the filter processing time of the output of the intake pressure detection record,
The processing delay correction amount can be obtained more accurately.

According to the fuel injection amount control method of the second aspect of the present invention, the processing delay correction pressure and the transient correction pressure for correcting the intake pipe pressure are obtained. That is, a processing delay correction value related to the sum of the time Δt1 from the fuel injection amount calculation timing to the intake valve closing timing and the filter processing time Δt2 of the output of the intake pressure detector,
The processing delay correction pressure is obtained by the third state quantity. Further, from the changing state of the third state quantity, the transient correction pressure is obtained based on the transient correction value that decreases from the initial stage of the transient period to the final stage of the transient period. Then, the fuel injection amount is obtained from the intake pipe pressure at the calculation timing, the processing delay correction pressure, and the transient correction pressure. Even by obtaining the fuel injection amount in this way, the optimum fuel for the internal combustion engine is obtained. The injection amount can be obtained with high accuracy. Also in this method, since the processing delay correction pressure is calculated in consideration of the filter processing time of the output of the intake pressure detector, the processing delay correction pressure can be calculated more accurately.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a control device 1 of an internal combustion engine according to an embodiment of the present invention and a configuration related thereto, FIG. 2 is a block diagram showing a specific configuration of the control device 1, and FIG. 3 is a throttle valve opening. 4 is a timing chart for explaining the operation at the time of the transient when the degree is changed, FIG. 4 is a graph showing the relationship between the intake air flow rate Qin to the surge tank 6 and the outflow air outflow Qout, and FIG. 5 is the opening of each throttle valve. Intake pressure P, Pc
6 is a graph showing the change of the value MAP with respect to the change of the fuel injection amount, FIG. 6 is a timing chart showing the correction amount by the simultaneous injection control, and FIGS. 7 to 10 are flow charts for explaining the operation.
FIG. 11 is a graph showing the change of the correction coefficient K5a of the calculated value Pc of the intake pressure with respect to the change of the cooling water temperature, and FIG. 12 is a flow chart for explaining the operation of another embodiment of the present invention.
The figure is a timing chart for explaining the simultaneous injection control. 1 ... Control device, 4, 7 ... Intake pipe, 5 ... Slot valve, 6 ... Surge tank, 10 ... Internal combustion engine, 14 ... Exhaust pipe, 20-31 ... Detector, 43 ... Processing Circuit, 45 ... Memory, B1-Bm ... Fuel injection valve, E1-Em ... Combustion chamber

 ─────────────────────────────────────────────────── ───Continued from the front page (56) Reference JP-A 63-215848 (JP, A) JP-A 1-216054 (JP, A) JP-A 62-162750 (JP, A) JP-A 63- 289237 (JP, A) JP-A-2-136531 (JP, A) JP-A 1-216041 (JP, A) JP-A-3-37345 (JP, A) JP-A-58-211535 (JP, A) JP 59-201937 (JP, A) Actual Kaihei 1-160148 (JP, U)

Claims (2)

(57) [Claims] 1. A fuel injection amount control method for an internal combustion engine, wherein a fuel injection valve is provided corresponding to each of all combustion chambers, and the fuel injection valve simultaneously injects fuel for each revolution of the internal combustion engine. The basic injection amount is obtained based on the intake pipe pressure at a predetermined calculation timing, and the first state amount related to the air flow rate passing through the throttle valve is obtained based on the opening of the throttle valve. A second state quantity related to the flow rate of the air supplied to the internal combustion engine is obtained by following the change with a time delay, and is related to the time change rate of the intake pipe pressure from the difference between the first state quantity and the second state quantity. The calculated third state quantity is calculated, and the processing delay correction value related to the sum of the time Δt1 from the fuel injection amount calculation timing to the intake valve closing timing and the filter processing time Δt2 of the output of the intake pressure detector, and the third Depending on the state quantity A logical delay correction amount, and a transient correction amount based on a transient correction value that decreases from the change state of the third state quantity from the transition initial stage to the transition final stage, the basic injection amount and the processing delay. A method for controlling a fuel injection amount of an internal combustion engine, characterized in that a fuel injection amount is obtained from a correction amount and the transient correction amount. 2. A fuel injection amount control method for an internal combustion engine, wherein a fuel injection valve is provided corresponding to each of all combustion chambers, and the fuel injection valve simultaneously injects fuel for each revolution of the internal combustion engine. Based on the opening of the throttle valve, a first state quantity related to the air flow rate passing through the throttle valve is obtained, and the first state quantity is tracked and changed with a time delay, and the air flow rate supplied to the internal combustion engine. Is calculated from the difference between the first state quantity and the second state quantity, and the third state quantity is calculated from the difference between the first state quantity and the second state quantity, and the intake valve is calculated from the fuel injection amount calculation timing. The processing delay correction value related to the sum of the time Δt1 until the closing timing and the filter processing time Δt2 of the output of the intake pressure detector and the third state quantity are used to obtain the processing delay correction pressure. From changing state, during transition The transient correction pressure is calculated based on the transient correction value that decreases from the period to the end of the transition time, and the fuel injection amount is calculated using the intake pipe pressure at the calculation timing, the processing delay correction pressure, and the transient correction pressure. A method for controlling a fuel injection amount of an internal combustion engine, comprising: