JPS62203955A - Fuel injection method for internal combustion engine - Google Patents

Abstract

PURPOSE:To improve operation characteristic by calculating a 1st and a 2nd weighted averages of suction pressures excluding pulsations and, at the time of performing asynchronous fuel injection under a condition where deviations of the said averages are more than a specified value, by making the 2nd weighted average the 1st weighted average during deceleration. CONSTITUTION:During operation of an engine, an electronic control circuit 44 detects a present 1st weighted average PM0 expressed by a 1st weighted average of a suction pipe pressure detected in the past by means of a pressure sensor 6 and by a present suction pipe pressure. Also, a present 2nd weighted average PM1i expressed by a 2nd weighted average of the suction pipe pressure detected in the past with a greater weight than the 1st weighted average and by a present suction pressure is detected. And when deviations of the averages PM0 and PM1i are more than a specified value, a fuel injection valve 24 is controlled to perform asynchronous injection. Also, the value of the 1st weighted average PM0 is set to the value of the 2nd weighted average PM1i.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a fuel injection method for an internal combustion engine, and particularly to a method for injecting fuel asynchronously with a crank angle under predetermined operating conditions, that is, regardless of the crank angle. The present invention relates to a fuel injection method for an internal combustion engine.

[Prior art] Basic fuel injection 34 based on intake pipe pressure PM and engine speed NE
In an internal combustion engine that performs fuel injection by determining the basic fuel injection time corresponding to The pressure sensor output is input to the control circuit via a large filter. The control circuit determines the basic fuel injection time corresponding to the basic fuel injection TP based on the engine rotational speed and the detected value of the intake pipe pressure that is input through a filter that is delayed with respect to the change in the actual intake pipe pressure. At the same time, by correcting this basic fuel injection time according to the intake air temperature, engine cooling water temperature, etc., the fuel injection time corresponding to the fuel injection amount TAU is determined, and the fuel injection time is determined at each predetermined crank angle, that is, in synchronization with the crank angle. The injection valve is opened and fuel corresponding to the fuel injection amount TAU is injected into each cylinder, each cylinder group, or all cylinders. In such an internal combustion engine, in addition to synchronous fuel injection synchronized with the crank angle as shown in L, asynchronous fuel injection is performed asynchronously with the crank angle in order to improve responsiveness during acceleration. By executing this asynchronous fuel injection, even if the intake pipe pressure suddenly increases during acceleration, the fuel supplied to the engine is increased by the asynchronous fuel injection, and the air-fuel ratio during acceleration approaches the engine-required air-fuel ratio. be able to.

Conventionally, as asynchronous fuel injection, the pressure sensor output input through a filter is sampled at a predetermined period, and when the difference between the current sampled value and the previous sampled value is greater than or equal to a predetermined value, asynchronous fuel injection is performed. (Japanese Unexamined Patent Publication No. 59-90728) and a method of performing asynchronous fuel injection when the second-order differential value with respect to time of the pressure sensor output input via a filter is equal to or greater than a predetermined value (Japanese Unexamined Patent Publication No. 59-90728). -39938) has been carried out.

[Problems to be Solved by the Invention] However, conventional filters have a relatively large time constant in order to remove the pulsating component of the intake pipe pressure (the level of the pulsating component reaches its maximum when the throttle is fully open; In order to remove the pulsation component under all operating conditions, the time constant must be determined to match when the throttle is fully open), so the rise of the signal input through the filter is delayed relative to the actual change in intake pipe pressure. The timing of asynchronous fuel injection is delayed. There was a problem. For this reason, asynchronous fuel injection is no longer executed at the initial stage of acceleration, resulting in deterioration of acceleration performance at the initial stage of acceleration, and asynchronous fuel injection is executed after the initial stage of acceleration when the intake pipe pressure has become relatively high. , the amount of evaporation decreases, fuel adheres to the inner wall of the intake manifold, and the amount of fuel supplied to the engine decreases.

On the other hand, in order to solve the above problems and improve the responsiveness of asynchronous fuel injection timing, a relatively small time constant (for example,
3 to 5 m5ec) It is possible to input the pressure sensor output to the control circuit through a filter, but since the pulsating component cannot be completely removed by the filter, the sampling value is There is a problem in that asynchronous fuel injection is performed when the difference between the two or the second-order differential value exceeds a predetermined value. In order to solve this problem, increasing the predetermined value may be considered, but there is a problem that asynchronous fuel injection will not be performed at the required timing during acceleration. Therefore, acceleration performance and exhaust emissions deteriorate.

In order to solve this problem, the present inventors used a filter with a relatively small time constant, calculated a weighted average value by removing the pulsating component of the intake pipe pressure based on the filter output, and calculated the weighted average value from the filter output. A method has already been proposed in which asynchronous fuel injection is performed when the deviation obtained by subtracting the average value becomes equal to or greater than a positive predetermined value. According to this method, the way the filter comes out changes in accordance with changes in the actual intake pipe pressure, so that the start of acceleration can be detected based on the magnitude of the deviation, thereby making it possible to perform asynchronous fuel injection at the start of acceleration.

However, when the four-way state changes from deceleration to acceleration, such as during a gear change, the filter output PMo follows the actual intake pipe pressure and points at point A (
(at the start of acceleration), the weighted average value PM1 of the intake pipe pressure is delayed with respect to the filter output PMo, so the deviation becomes 0 at point B, which is delayed by a predetermined time from point A. , Asynchronous fuel injection will be performed after point B. Therefore, a problem arises in that the air-fuel ratio becomes lean during the period from point A to point B, resulting in deterioration of acceleration performance and exhaust emissions.

The uninvented invention was made to solve the above problem, and even when the driving state shifts from deceleration to acceleration, it is possible to inject asynchronous fuel at a timing appropriate to the start of acceleration without being affected by the pulsating component of the intake pipe pressure. An object of the present invention is to provide a fuel injection method for an internal combustion engine that enables the execution of the following steps.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a method for calculating the past intake pipe pressure when the weight of the first weighted average value detected in the past of the intake pipe pressure is changed. A current first weighted average value expressed by the first weighted average value detected in the past and the current intake pipe pressure detected is detected, and a second weighted average value detected in the past of the intake pipe pressure is detected. a current second weight expressed by a previously detected second weighted average value of intake pipe pressure and a detected current intake pipe pressure when the weight of the value is heavier than the first weighted average value; Detect the average value with
A deviation is obtained by subtracting the second weighted average value of the currently detected intake pipe pressure from the first weighted average value of the currently detected intake pipe pressure, and when the deviation exceeds a predetermined value, the crank angle is A fuel injection method for an internal combustion engine in which fuel is injected non-repetitively, characterized in that during deceleration, the current first weighted average value is set as the current second weighted average value. shall be.

The first weighted average value and the second weighted average value can be detected by calculating the following general formula.
The weighted average value of can be detected by passing the pressure sensor output that detects the intake pipe pressure through a filter having a time constant large enough to remove the pulsating component of the intake pipe pressure. Calculate the following equation (1) by using a signal outputted from a pressure sensor that detects pressure via a filter having a time constant that is large enough to remove a pulsating component of intake pipe pressure as the detected current intake pipe pressure. It can be detected by

PML+ (K-1)PMi, -1 PMi, =□ ・ ・ ・ (1) Here, PML is the current intake pipe pressure detected by the pressure detection means, and PML- is the current intake pipe pressure. The past detected weighted average value, P M t, is the currently detected weighted average value of the intake pipe pressure, and K is a constant corresponding to the weight.

[Function] The present invention will be explained in detail below. In the above equation (1), if the constant K is made small (for example, 4), the first weighted average value PMo can be detected, and if the constant K is made larger (for example, 1
6 or 32) and the second weighted average value PMl can be detected. Here, by setting the value of the constant to an appropriate value, the first weighted average value including the pulsating component of the intake pipe pressure that does not affect the asynchronous fuel injection and the pulsating component of the intake pipe pressure can be calculated. The removed second weighted average value can be detected, and the first weighted average value including the pulsating component can be detected as J! The second weighted average value changes rapidly by +i following the change in the actual intake pipe pressure, and the second weighted average value changes gradually with respect to the actual change in the intake pipe pressure. Therefore, the deviation of the first weighted average value including the pulsating component is calculated based on the second weighted average value from which the pulsating component is completely removed, and this deviation is a positive predetermined value (second weighted average value). Changes in intake pipe pressure due to acceleration can be detected by determining whether the value exceeds the maximum value of the pulsation component (based on the reference value).

This makes it possible to perform asynchronous fuel injection in a manner appropriate to the start of acceleration. Also, during deceleration, the first weighted average value is set to the second weighted average value, so the first weighted average value changes to follow the change in the actual intake pipe pressure. On the other hand, the second weighted average value changes gradually with respect to changes in the actual intake pipe pressure from the time when deceleration shifts to acceleration. Therefore, the deviation between the first weighted average value and the second weighted average value takes a positive value from the time of transition from deceleration to acceleration, that is, from the start of acceleration, and the start of acceleration is detected from this deviation. As a result, asynchronous fuel injection can be performed in accordance with the start of acceleration when transitioning from deceleration to acceleration.

[Effects of the Invention] As explained above, according to the present invention, asynchronous fuel injection can be performed at the necessary timing when transitioning from deceleration to acceleration without being affected by the pulsating component of the intake pipe pressure. Effects can be obtained.

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

FIG. 3 shows an internal combustion engine to which the present invention can be applied. A throttle valve 8 is disposed downstream of an air cleaner (not shown), and a throttle valve shaft is attached to the throttle valve 8. A linear throttle sensor 10 is installed, which is composed of a contact fixed to the throttle valve 8 and a resistor in contact with the contact, and outputs a voltage proportional to the opening of the throttle valve 8. A surge tank 12 is installed downstream of the throttle valve 8. The surge tank 12 is equipped with a semiconductor strain resistance type pressure sensor 6 connected to a filter with a time constant of about 3 to 5 I!1 SeC. A bypass passage 14 is also provided to communicate the upstream side of the throttle valve and the surge tank 12 on the downstream side of the throttle valve.
4 is an idle speed control (I) whose opening degree is adjusted by a pulse motor 16A equipped with a 4-pole stator.
SC) Valve 16B is installed. The surge tank 12 is connected to the intake manifold 18 and the intake boat 2.
2 to the combustion chamber of the engine 20. A fuel injection valve 24 is attached to the intake manifold 18 for each cylinder or for each cylinder group so as to protrude into the intake manifold.

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 3° is attached to the exhaust manifold 28 for outputting an air-fuel ratio signal that is inverted at the residual oxygen concentration in the exhaust gas corresponding to 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.

A spark plug 38 is attached to each cylinder so as to penetrate the cylinder head 36 of the engine 20 and protrude into the combustion chamber. The spark plug 38 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 installed, each of which is composed of a signal rotor fixed to the distributor shaft and a pickup fixed to the distributor housing. In the case of a six-cylinder engine, the cylinder discrimination sensor 46 outputs a cylinder discrimination signal, for example, every 720'CA, and the rotation angle sensor 48 outputs an engine rotation speed signal, for example, every 30'CA.

As shown in FIG. 4, the electronic control circuit 44 includes a central processing unit (MPU) 60. Read Φ only memory (ROM) 6
2. Random access memory (RAM) 64. Backup RAM (BU-RAM) 66, input/output capo) 6
8. It is configured to include an input port (0° output port) 72, 74, and 76, and a bus 78 such as a data bus or a control path that connects these. For the entrance and exit capotro 8.

Analog-to-digital (A/D) converter 78. The filter 7, pressure sensor 6, cooling water temperature sensor 34, and throttle sensor 10 are connected via a multiplexer 80 and buffers 82, 83, and 84. The MPU 60 controls the multiplexer 80 and the A/D converter 78, and outputs the pressure sensor 6 and the water temperature sensor 3 which are input through the filter 7.
4 outputs and the throttle sensor 10 output are sequentially converted into digital signals and stored in the RAM 64. Input port door 0 is connected to input port 02 via converter 88 and buffer 86.
The sensor 30 is connected, as well as a cylinder discrimination sensor 46 and a rotation angle sensor 48 via a waveform shaping circuit 90. The output port door 2 is connected to the igniter 42 via a drive circuit 92, the output port door 4 is connected to the fuel injection valve 24 via a drive circuit 94, and the output port door 6 is connected to the ISO valve via a drive circuit 96. It is connected to the pulse motor 16A. In addition, 98 is a clock, 1
00 is a timer. The ROM 62 stores in advance a control routine program, etc., which will be explained below.

Next, a control routine of an embodiment in which the present invention is applied to the above engine will be explained.

FIG. 5 shows the first embodiment at every 180° CA or
This shows a synchronous fuel injection amount calculation routine that is executed every °CA.In step 110, the intake pipe pressure is inputted from the pressure sensor 6 via the filter 7, A/D converted, and stored in the RAM. Weighted average value PMo of 1
(PMo L) and engine speed NE, etc.
In step 112, basic fuel injection ff1TP is calculated based on the first weighted average value PMO of the intake pipe pressure and the engine speed NE. Then, in step 114, the basic fuel injection amount TP is corrected based on the air-fuel ratio feedback correction coefficient obtained based on the 02 sensor output, the intake air temperature, the engine cooling water temperature, etc., and the fuel injection amount TAU is calculated. Then, in a fuel injection amount control routine (not shown), the fuel injection valve is opened for a time corresponding to the fuel injection amount TAU in synchronization with the crank angle (for example, at intake top dead center), and fuel is injected.

FIG. 1 shows the main routine of this embodiment, which is executed at predetermined time intervals (for example, every 12 m5ec) or at predetermined crank angles, and in step 116, the data is A/D converted and stored in the RAM. Current throttle opening TAL and previous throttle opening TAL-
1, and in step 118°, the rate of change ΔTA of the throttle opening is calculated by subtracting the previous throttle opening TAL- from the current throttle opening TA&.

In step 120, the rate of change Δ of the throttle opening is
By determining whether TA is negative or not, it is determined whether or not deceleration is currently in progress. When it is determined that deceleration is in progress, in step 122, the rate of change ΔTA of throttle opening is set to a negative predetermined value LTA to prevent chattering. Determine whether it is less than or not. Then, when the determination in step 122 is 11 constant, in step 124, the current first weighted average value PMoL obtained by A/D converting the output of the filter 7
In step 126, the value of the current first weighted average value PMoL is changed to the current second weighted average value PMoL.
Set to the MIL value.

As a result, when it is determined that deceleration is occurring in step 120, as shown in FIG. The first weighted average value PMoL is set to the value of the first weighted average value PMoL.

In step 120, the rate of change ΔTA of the throttle opening is
When it is determined that the change rate ΔTA of the throttle opening is greater than or equal to the predetermined value LTA in step 122, it is determined that acceleration is in progress, and the current first weighted average is calculated in step 128. The value PMa L is taken and the current second weighted average value PM,L is calculated in step 130 according to the following equation.

PMOL + (Kt -1) PM, L LPM port = 1 to □ (2) However, PMlL-1 is the past second weighted average value,
K1 can be easily calculated digitally if it is a number of 4, 16, or 32, but it is determined to suit various engines.

In step 132, the current first weighted average value PM
The deviation ΔPM is calculated by subtracting the current second weighted average value PM, L from o1, and in step 134 it is determined whether the deviation ΔPM is greater than or equal to a positive predetermined value TR. In step 134, the deviation ΔPM is a positive predetermined value TR.
When it is determined that the above is the case, it is determined that there is a request for asynchronous fuel injection, and in step 136, the asynchronous fuel injection amount TAUASY is calculated according to the following formula.

TAUASY = 2 - Δ PM Fist (3) However, K2 is a constant.

Then, in step 138, the asynchronous fuel injection HrA
The fuel injection valve is opened for a time corresponding to uAsy to perform asynchronous fuel injection. If it is determined in step 134 that the deviation ΔPM is less than the predetermined value TR, the next routine is executed as is.

Note that the two-legged step 122 can be omitted, and the asynchronous fuel injection amount TAUASY in step 136 can be omitted.
may be a constant value.

As a result of the above, when the operating state shifts from deceleration to acceleration, the rate of change ΔTA of the throttle opening changes from negative to positive, so acceleration from deceleration can be detected, and
When transitioning from deceleration to acceleration, as shown in Figure 6,
Since the first weighted average value PM0 changes approximately following changes in the actual intake pipe pressure, and the second weighted average value PM changes gradually with respect to changes in the actual intake pipe pressure,
When the deviation ΔPM of the weighted average value from the change point from deceleration to acceleration (point A) becomes 0 or more, and the deviation ΔPM becomes more than the predetermined value TR, asynchronous fuel injection is executed. Here, since the first weighted average value PMo substantially follows the pressure sensor output, the engine pulsation component cannot be completely removed.
By comparing the weighted average value PM of This makes it possible to determine whether or not acceleration has started, thereby making it possible to perform asynchronous fuel injection simultaneously with the start of acceleration.

A second embodiment of the present invention will be described with reference to FIGS. 7 and 8. In this embodiment, deceleration and acceleration are detected from the rate of change of the first weighted average value, and asynchronous fuel injection is executed in the same manner as in the first embodiment. Therefore, in FIG. 7, parts corresponding to those in FIG. 1 are denoted by the same reference numerals, and explanation thereof will be omitted. In step 140, the first weighted average value PMoL calculated this time and the first weighted average value PMoz-t calculated last time are taken in, and in step 142, the current first weighted average value PMOL is taken in.
The rate of change ΔPMo of the first weighted average value is calculated by subtracting the previous first weighted average value PMoLt from . Then, in step 144, it is determined whether the driving state has shifted from deceleration to acceleration by determining whether the rate of change ΔPMo of the first weighted average value is negative.

The first weighted average value PMO is as shown in FIG.
Since it changes from a decrease to an increase at the point of change from deceleration to acceleration (point A), it is possible to determine whether it is deceleration or acceleration by determining whether the rate of change ΔPMo of the first weighted average value is negative or not. When it is determined that the deceleration is in progress, the first weighted average value PMO is determined in step 12B as in the first embodiment.
The value of L is set to the value of the second weighted average value PMI L, and when it is determined that acceleration is in progress, asynchronous operation is performed by determining whether the deviation ΔPM is greater than or equal to the predetermined value TR in the same way as in the first embodiment. Asynchronous fuel injection is performed by calculating the fuel injection amount.

As a result of the above, as shown in FIG. 8, asynchronous fuel injection is executed at the transition point from deceleration to acceleration. Note that, as in the first embodiment, the value of PMOL may be set as the value of PMIL when PMΔ0 is less than a predetermined negative value.

Next, a third embodiment of the present invention will be described with reference to FIG. 9 and FIG. By determining whether the deviation ΔPM from the value PMI L is negative or not, it is determined whether deceleration or acceleration is to be performed, and asynchronous fuel injection is executed in the same manner as in the first embodiment. Therefore, in Figure 9, the first
Portions corresponding to those in the figures are given the same reference numerals and explanations will be omitted.

In step 146, the current first weighted average value PMo&, which has been A/D converted and is stored in the RAM, is calculated with the previous second weighted average value PMIL-t, which is stored in the RAM. In the zero-order step 150, the current second weighted average value PMI L is calculated according to the above equation (2) in step 148. The deviation ΔPM of the weighted average value is calculated by subtracting the weighted average value PM1. And step 1
52, it is determined whether the deviation ΔPM is negative or not to determine whether it is deceleration or acceleration, and when it is determined that it is deceleration, the current weighted average value PM PM is determined as in the first embodiment.
The value of a is set to the current second weighted average value PMIL. On the other hand, when the deviation ΔPM is determined to be 0 or more and the acceleration state is determined, the asynchronous fuel injector T A is determined by determining whether the deviation ΔPM is equal to or greater than a positive predetermined value TR
Asynchronous fuel injection is performed by calculating UASY.

Here, the current second weighted average value PM, L is calculated according to the above equation (2) in step 148, and the current first weighted average value PM, L is calculated in step 126.
OL is set to the value of the current second weighted average value PMI l, but if the first weighted average value PMOL changes by dPMo within the calculation time (the above-mentioned predetermined time), the current second weighted average value is changed. PMI, changes by d PM,/. This amount of change d P Mo / K s is determined in step 1.
50 to obtain the deviation ΔPM. On the other hand, as understood from FIG. 10, the change idPM, / takes a negative value during deceleration and a positive value during acceleration.

Therefore, by determining whether the deviation ΔPM is positive or negative, it is possible to determine whether the vehicle is decelerating or accelerating.

FIG. 10 shows the timing when asynchronous fuel injection is executed as described above.

A fourth embodiment of the present invention will be described with reference to FIG. 11 and FIG. In this system, it is determined whether deceleration or acceleration is to be performed based on the deceleration or acceleration, and the magnitude of the predetermined value TR for executing asynchronous fuel injection is changed depending on the deceleration or acceleration. Therefore, in FIG. 11, parts corresponding to those in FIG. 7 are given the same reference numerals, and their explanation will be omitted.

When it is determined that deceleration is occurring in step 144, in step 126, the current first weighted average value PMOL is changed to the current second weighted average value P.
The constant β is set to the value of MI L in step 154.
is set to a predetermined value TR. On the other hand, when it is determined in step 144 that acceleration is in progress and it is determined in step 134 that there is a request for asynchronous fuel injection, the constant α is set to a predetermined value of TR in step 156, and asynchronous fuel injection is performed in the same manner as described above. Here, the 12th
As shown in the figure, the constant β is set smaller than the constant α.

Therefore, the predetermined value TR for asynchronous fuel injection request during deceleration
is made smaller than the predetermined value TR for requesting asynchronous fuel injection during acceleration ((2) in FIG. 12).

Therefore, the first asynchronous fuel injection when transitioning from deceleration to acceleration is performed according to the comparison result between the deviation ΔPM and the constant β, and the second and subsequent asynchronous fuel injections are performed according to the comparison result between the deviation ΔPM and the constant β.
As a result of the above, according to the present embodiment, since the asynchronous fuel injection is executed at a time when the magnitude of the deviation ΔPM is small, the above-mentioned first to third Asynchronous fuel injection can be performed at earlier timing than in the embodiment. In addition, Fig. 12 (
1) shows the timing of conventional asynchronous fuel injection.

Next, a fifth embodiment of the present invention will be described with reference to FIG. In this embodiment, the rate of change ΔP of the first weighted average value
Deceleration and acceleration are determined by determining whether MO is positive or negative, and the magnitude of the predetermined value TH for asynchronous fuel injection request is changed between deceleration and acceleration. .

Therefore, in FIG. 13, parts corresponding to those in FIGS. 9 and 11 are given the same reference numerals and their explanations will be omitted. Note that in this embodiment, as in the first embodiment, it may be determined whether the rate of change ΔPM of the accelerator opening is positive or negative to determine whether it is deceleration or acceleration. As shown in the example, deceleration or acceleration may be determined by determining whether the rate of change ΔPMo of the first weighted average value is positive or negative.

As explained above, according to the above embodiment, by changing the coefficient K corresponding to the weighting, it is possible to change the weight and remove the influence of the pulsating component of the intake pipe pressure. It is possible to use a new filter and perform asynchronous fuel injection at a faster timing than conventionally. By speeding up the execution timing of asynchronous fuel injection in this manner, it is possible to improve exhaust emissions and acceleration performance. In addition, in the case of asynchronous fuel injection triggered by the second-order differential value of the intake pipe pressure, the number of words for calculating the second-order differential value is required, so the total number of words increases, but in this example, the weighted average Since the deviation of the values is calculated, the number of words on the software can be reduced.
Furthermore, the execution timing of asynchronous fuel injection can be made faster with simple logic. Furthermore, since the soft logic can be integrated into a fuel injection system that performs synchronous fuel increase based on a weighted average value of intake pipe pressure, the logic can be simplified.

Note that in the above example, the first weighted average value is detected using a signal passed through a filter.
The first weighted average value may be detected by performing v4 calculation after passing through a filter, or the first weighted average value may be detected by calculation from the pressure sensor output without passing through a filter. You can do it like this. Further, the second weighted average value may be directly detected by calculation from the pressure sensor output, or all weighted average values may be detected using a filter.

[Brief explanation of drawings]

FIG. 1 is a flowchart showing the asynchronous fuel injection routine of the first embodiment of the present invention, FIG. 2 is a diagram showing conventional asynchronous fuel injection timing, and FIG. 3 is a schematic diagram showing an engine to which the present invention is applicable. 4 is a block diagram showing the details of the control circuit shown in FIG. 3, FIG. 5 is a flowchart showing the synchronous fuel injection amount calculation routine according to the embodiment of the present invention, and FIG. 6 is a block diagram showing the details of the control circuit of FIG. A diagram showing the asynchronous fuel injection timing; FIG. 7 is a flowchart showing the asynchronous fuel injection routine of the second embodiment of the present invention; FIG. 8 is a diagram showing the asynchronous fuel injection timing of the second embodiment; FIG. 9 is a flowchart showing the asynchronous fuel injection routine of the third embodiment of the present invention, and FIG.
Diagram showing the asynchronous fuel injection timing of the embodiment of
1 is a flowchart showing the asynchronous fuel injection routine of the fourth embodiment of the present invention, FIG. 12 is a diagram showing the asynchronous fuel injection timing of the fourth embodiment, and FIG. 13 is a flowchart showing the asynchronous fuel injection routine of the fourth embodiment of the present invention.
3 is a flow diagram illustrating an example asynchronous fuel injection routine. 6＠Write/pressure sensor, 7...filter. 24...Fuel injection valve. 301/02 sensor.

Claims (3)

[Claims] (1) When the weight of the first weighted average value detected in the past of the intake pipe pressure is increased, the first weighted average value detected in the past of the intake pipe pressure and the detected current intake pipe pressure are Intake pipe pressure when the current first weighted average value expressed is detected and the weight of the second weighted average value detected in the past of the intake pipe pressure is made heavier than the first weighted average value. The current second weighted average value expressed by the second weighted average value detected in the past and the current detected intake pipe pressure is detected, and the first weighted average value of the currently detected intake pipe pressure is detected.
An internal combustion engine that calculates a deviation by subtracting a second weighted average value of the currently detected intake pipe pressure from the weighted average value of A fuel injection method for an internal combustion engine, characterized in that during deceleration, the current first weighted average value is set as the second weighted average value. (2) The current first weighted average value is detected by passing the pressure sensor output that detects the intake pipe pressure through a filter having a time constant large enough to remove the pulsating component of the intake pipe pressure. A fuel injection method for an internal combustion engine according to claim (1). (3) The current first weighted average value is determined by the signal output from the pressure sensor that detects the intake pipe pressure through a filter having a time constant that is large enough to remove the pulsating component of the intake pipe pressure. A fuel injection method for an internal combustion engine according to claim (1), wherein the current intake pipe pressure is detected as the current intake pipe pressure.