JP2002039009A - Intake volume detecting unit and fuel injection quantity control unit of engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a signal corresponding to ideal cylinder intake volume in a D-JETRONIC system. SOLUTION: An arithmetic means 22 calculates a delay processing value for a detected value of an intake pipe pressure. On the other hand, an arithmetic means 23 calculates a volumetric flow rate at a throttle valve portion based on an accel-opening, or a throttle valve opening. An arithmetic means 24 calculates a one-time delay processing value taking into consideration a delay of transient intake pipe pressure for the volumetric flow rate. An arithmetic means 25 calculates a two-times delay processing value so that a delay processing value and a phase of said detected value are equal to those of the one-time delay processing value. Then, an arithmetic means 26 calculates the signal corresponding to the cylinder intake volume by correcting the delay processing value for the detected value based on the ratio of the one-time delay processing value to the two-times delay processing value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for detecting an amount of intake air (hereinafter, simply referred to as "cylinder intake") flowing into a cylinder of an engine, and to control a fuel injection amount based on the detected cylinder intake amount. Related to the device.

[0002]

2. Description of the Related Art An engine having a so-called D-jetronic type fuel injection device which calculates a fuel injection amount based on an intake pipe pressure downstream of a throttle valve (hereinafter simply referred to as "intake pipe pressure") and an engine rotation speed. Since the intake pipe pressure fluctuates under the influence of intake pulsation, the influence of intake pulsation is removed by passing a sensor detection value PM of the intake pipe pressure sensor through a low-pass filter. In this case, when the fuel injection amount is calculated based on the signal after passing through the low-pass filter (the one-time processing value of the intake pipe pressure) PMi, the air-fuel ratio leans to the lean side from the target value during acceleration. For the signal PMi, PMDi = PMi × L + PMDi _n−1 × (1−L) (1) where L: weighted average coefficient, PMDi _n−1 : previous value of PMDi, and delay processing is performed by the following equation. Based on this delay processing value (two-time delay processing value of the intake pipe pressure) PMDi and the signal PMi after passing through the low-pass filter, PMOS = 2 PMi−PMDi (2) And a fuel injection amount corresponding to cylinder intake is calculated from the PMOS and the engine speed (Japanese Patent Laid-Open No. 60-156).
947).

As shown in FIG. 19, the difference between the signal PMi after passing through the low-pass filter and the delay processing value PMi after passing through the low-pass filter, as shown in FIG. The sensor detection value P is obtained by adding the amount of PMDi (see hatching).
Intake pipe pressure signal PMOS (= P
Mi + (PMi-PMDi)), and the new intake pipe pressure signal PMOS is used to supply more fuel than the sensor detection value PM to prevent the air-fuel ratio from becoming lean during acceleration.

[0004]

The intake pipe pressure is a signal corresponding to the cylinder intake. The signal corresponding to the cylinder intake does not fluctuate due to the influence of the intake pulsation, and the actual phase of the cylinder intake. Ideally, there should be no delay or advance.

However, since the intake pipe pressure signal PMOS of the conventional device is generated to prevent the air-fuel ratio from becoming lean during acceleration, the sensor detection value P of the intake pipe pressure is used.
The phase is advanced from M, and the air-fuel ratio becomes richer by the difference.

Accordingly, the present invention calculates the throttle valve volume flow rate based on the accelerator opening or the throttle valve opening, and calculates the intake pipe pressure during transient (acceleration or deceleration) with respect to the throttle valve volume flow. A one-time delay processing value is calculated in consideration of the delay of the intake pipe pressure, and a two-time delay processing value is calculated with respect to the one-time delay processing value so that the delay processing value of the intake pipe pressure detection value has the same phase. The delay processing value of the intake pipe pressure detection value is calculated by the ratio of the one-time delay processing value and the two-time delay processing value (this is D
A signal equivalent to the cylinder intake in the D-Jetronic system is newly obtained by correcting the corrected value of the signal corresponding to the conventional cylinder intake in the J-Etronic system into a signal equivalent to the ideal cylinder intake in the D-Jetronic system. Is obtained by correcting the signal of the cylinder intake air amount similarly calculated in the L-Jetronic system by the ratio between the one-time delay processing value and the two-time delay processing value. An object of the present invention is to obtain an ideal cylinder intake air amount signal in the L-Jetronic system by using an intake air amount signal.

A fuel injection amount equivalent to cylinder intake is obtained by using a signal corresponding to an ideal cylinder intake amount in the D-Jetronic system and an ideal cylinder intake amount signal in the L-Jetronic system. The purpose of this is to obtain a flat air-fuel ratio characteristic before and after acceleration / deceleration.

Further, when calculating the fuel injection amount corresponding to the cylinder intake, it is necessary to take into account the difference in the fuel injection method, such as whether to inject into the intake port or directly into the combustion chamber. That is, in the case of intake port injection, a fuel injection amount equivalent to cylinder intake is calculated using a signal corresponding to an ideal cylinder intake amount in the D-Jetronic system or an ideal cylinder intake amount signal in the L-Jetronic system. In the early stage of the acceleration, the fuel becomes insufficient and the air-fuel ratio leans to the lean side, and hesitation occurs, resulting in poor drivability and poor exhaust performance. Therefore, in the present invention, in the case of port injection, a preemption value obtained by performing a preemption correction on the one-time delay processing value of the throttle valve section volume flow rate is calculated, and this preemption value is replaced with the one-time delay processing value. An object of the present invention is to improve the response performance and the exhaust performance at the initial stage of acceleration even in the case of port injection by using the values.

[0009]

According to a first aspect of the present invention, as shown in FIG. 20, a means 21 for detecting an intake pipe pressure MAP,
Means 22 for calculating a delay processing value MAPav of this detection value
A means 23 for calculating a volume flow rate of the throttle valve portion based on the accelerator opening or the throttle valve opening;
A means 24 for calculating a delayed processing value, and a means 25 for calculating a delayed processing value twice so that the phase of the delayed processing value MAPav of the detected value is the same as that of the one-time delayed processing value.
And a means 26 for calculating, as a signal corresponding to cylinder intake, a value obtained by correcting the delay processing value MAPav of the detected value by the ratio of the one-time delay processing value and the two-time delay processing value.

The second invention comprises, as shown in FIG. 21, means 31 for detecting the mass flow rate upstream of the throttle valve, means 32 for calculating a delay processing value for the detected value in consideration of intake pulsation, A means 33 for calculating a delay processing value in consideration of a transition delay due to the presence of the intake pipe volume with respect to the delay processing value, and calculating a volume flow rate of the throttle valve portion based on the accelerator opening or the throttle valve opening. Means 23 for performing
Means 24 for calculating a one-time delay processing value taking into account the delay of the intake pipe pressure at the time of transient with respect to this volume flow rate; Means 25 for calculating a twice-delayed processing value so as to be the same, and a delay processing value taking into account a transitional delay caused by the presence of the intake pipe volume by a ratio of the one-time delayed processing value and the two-times delayed processing value Means 34 for calculating the corrected value as a signal of the cylinder intake air amount.

In a third aspect of the present invention, in the first or second aspect, a volume flow ratio is used instead of the volume flow rate.

According to a fourth aspect of the present invention, in the first or second aspect, a learning function corresponding to a throttle valve attachment error with respect to the throttle valve opening is provided.

As shown in FIG. 22, a fifth aspect of the present invention provides a means 21 for detecting an intake pipe pressure MAP, a means 22 for calculating a delay processing value MAPav of the detected value, an accelerator opening or a throttle valve opening. Means 23 for calculating the volume flow rate of the throttle valve portion based on the above, means 24 for calculating a one-time delay processing value for the volume flow rate taking into account the delay of the intake pipe pressure during transition, and Means 25 for calculating a twice-delayed processing value such that the detected processing value has the same phase as the delayed processing value MAPav with respect to the detected value; Means for calculating a value obtained by correcting the delay processing value MAPav as a signal corresponding to cylinder intake, means 41 for calculating a fuel injection amount based on the signal, and means for supplying the fuel of this injection amount to the engine. Equipped with a.

According to a sixth aspect of the present invention, as shown in FIG. 23, means 31 for detecting the mass flow rate upstream of the throttle valve, means 32 for calculating a delay processing value in consideration of the intake pulsation with respect to the detected value, A means 33 for calculating a delay processing value in consideration of a transition delay due to the presence of the intake pipe volume with respect to the delay processing value, and calculating a volume flow rate of the throttle valve portion based on the accelerator opening or the throttle valve opening. Means 23 for performing
Means 24 for calculating a one-time delay processing value taking into account the delay of the intake pipe pressure at the time of transient with respect to this volume flow rate; Means 25 for calculating a twice-delayed processing value so as to be the same, and a delay processing value taking into account a transitional delay caused by the presence of the intake pipe volume by a ratio of the one-time delayed processing value and the two-times delayed processing value Means 34 for calculating a value obtained by correcting as a signal of the cylinder intake amount, means 51 for calculating the fuel injection amount based on the signal, and means 42 for supplying the fuel of this injection amount to the engine.

According to a seventh aspect, in the fifth or sixth aspect, a volume flow ratio is used in place of the volume flow.

According to an eighth aspect of the present invention, in the fifth or sixth aspect, a learning function corresponding to a throttle valve mounting error with respect to the throttle valve opening is provided.

According to a ninth aspect, in the fifth aspect, when the means for supplying the fuel is provided in the intake port section, a prefetch value obtained by performing a prefetch correction on the one-time delay processing value is calculated. Then, a value obtained by correcting the delay processing value of the detection value with the ratio using the prefetch value instead of the one-time delay processing value is calculated as a signal corresponding to cylinder intake.

In a tenth aspect, in the sixth aspect, when the means for supplying the fuel is provided in the intake port, a prefetch value obtained by performing a prefetch correction on the one-time delay processing value is calculated. Then, a value obtained by correcting the delay processing value of the detection value with the ratio used in place of the prefetch value in place of the one-time delay processing value is calculated as a cylinder intake air amount signal.

According to an eleventh aspect of the present invention, in the ninth or tenth aspect, the preemption value is a linear relationship between the difference between the volume flow rate of the throttle valve portion and the one-time delay processing value and the delay of the intake pipe pressure during the transient. This is a value obtained by adding a prefetch correction value corresponding to a time constant equivalent value when it is regarded as a delay to the one-time delay processing value.

According to a twelfth aspect, in the fifth or sixth aspect, when the fuel supply means is provided facing the combustion chamber and the fuel is injected in the compression stroke, the fuel injection amount signal As a result, a dead time is given to delay the injection timing from the intake stroke to the compression stroke.

[0021]

According to the first, second and third aspects of the present invention, the one-time delayed processing value and the two-time delayed processing value of the volume flow ratio are signals based on the accelerator opening or the throttle opening, and thus are affected by intake pulsation. The influence of the intake pulsation is also eliminated from the delay processing value of the intake pipe pressure detection value in the D-Jetronic method and the delay processing value of the mass flow rate detection value upstream of the throttle valve in the L-Jetronic method. ing. Therefore, if the delay processing value of the intake pipe pressure detection value in the D-jetronic method is corrected by the ratio of the one-time delay processing value and the two-time delay processing value, for example, the ratio (>
1.0) as a correction magnification, the phase of the delay processing value of the detected intake pipe pressure value in the D-Jetronic method is advanced to the signal position of the detected intake pipe pressure value, thereby being not affected by intake pulsation, and An intake pipe pressure signal having neither a phase lag nor a phase advance with respect to the intake pipe pressure detected value at the time of transition is obtained.

Similarly, a delay processing value in consideration of a transitional delay due to the presence of the intake pipe volume in the L-Jetronic system using the above ratio as a correction factor during acceleration is used as a detected value of the mass flow rate upstream of the throttle valve. On the other hand, a delay processing value obtained when a delay processing value in consideration of a transitional delay due to the existence of the intake pipe volume is obtained without performing delay processing in consideration of intake pulsation (this is substantially equal to the actual cylinder intake air amount). The phase is advanced to the signal position of (1), whereby a signal of the cylinder intake air amount which is not affected by the intake air pulsation and has neither phase delay nor phase advance with respect to the actual cylinder intake air amount at the time of transition is obtained.

As described above, according to the first, second, and third aspects of the present invention, there is no fluctuation due to the influence of the intake air pulsation, and both the delay and the advance of the actual cylinder intake phase at the time of transition are obtained. A signal corresponding to an ideal cylinder intake amount in the non-D-Jetronic system and an ideal cylinder intake amount signal in the L-Jetronic system without delay or advance with respect to the phase of the actual cylinder intake amount can be obtained.

When the weighted average coefficient for calculating the one-time delay processing value of the volume flow rate of the throttle valve unit matches the reference throttle valve when there is no mounting error, the throttle valve is mounted. If the throttle valve is slightly open or close than the reference throttle valve used for matching due to an error, the weighted average coefficient will not match and an error will occur in the one-time delay processing value of the volume flow rate. The calculation accuracy of the signal corresponding to the ideal cylinder intake in the above and the signal of the ideal cylinder intake in the L-Jetronic system is deteriorated. However, according to the fourth and eighth inventions, the mounting error of the throttle valve is reduced. Even if there is, the calculation accuracy does not deteriorate.

The fifth, sixth, and seventh aspects of the present invention are directed to the case where fuel is directly supplied to the combustion chamber and the fuel is injected in the intake stroke. In this case, there is no fluctuation due to the influence of the intake pulsation, and there is no delay or advance with respect to the phase of the signal corresponding to the actual cylinder intake during the transition. By supplying the fuel injection amount calculated based on the signal of the ideal cylinder intake amount in the L-Jetronic system which does not lag or advance with respect to the signal or the phase of the actual cylinder intake amount at the time of transition, acceleration or The air-fuel ratio can be maintained at the target before and after deceleration.

The ninth, tenth, and eleventh inventions are directed to intake port injection. At the time of port injection, fuel wall flow becomes a problem, and the air-fuel ratio deviates from the target value to the lean side at the initial stage of acceleration, causing hesitation and deteriorating exhaust performance. The ninth, tenth, and eleventh inventions According to the above, the fuel is supplied more by the difference between the prefetch value and the one-time delay processing value, so that even in the case of the intake port injection, the air-fuel ratio does not become lean at the initial stage of the acceleration. Responsiveness and exhaust performance are improved.

According to the twelfth aspect, when the fuel is directly injected into the combustion chamber in the compression stroke (at the time of stratified combustion), the air-fuel ratio can be maintained at the target before and after acceleration or deceleration.

[0028]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, 1 is an engine body, 2 is an intake passage, 3 is an exhaust passage, 4 is a fuel injection valve, 5
Is a spark plug, 6 is a throttle valve, and 7 is this throttle valve 6.
A throttle valve control device (for example, a step motor, a DC motor, or the like) that electronically controls the opening degree of the motor. The fuel injection valve may be one that injects and supplies fuel toward the intake port.However, when performing stratified combustion described below, the fuel injection valve does not directly inject and supply fuel into the combustion chamber as illustrated. No.

There is no passage for bypassing the throttle valve 6. Accordingly, when it is necessary to increase the auxiliary air at the time of idling, the control unit 11 increases the opening of the throttle valve 6 by the increase of the auxiliary air.

Here, the outline of the control contents of the fuel injection will be described. The fuel injection valve injects the fuel in the latter half of the compression stroke at a low load or the like. A combustible air-fuel mixture is formed in a cavity in the vicinity of 5, and stratified combustion of fuel is caused by ignition by the ignition plug 5, and ultra-lean combustion with an air-fuel ratio exceeding 40 as a whole is performed. In the high load region, fuel is injected in the intake stroke to accelerate the mixing of fuel and air, fill the entire region of the combustion chamber with a homogeneous mixture, and perform homogeneous combustion with the mixture near the stoichiometric air-fuel ratio. Further, in an intermediate load region between the stratified combustion region and the homogeneous combustion region, lean combustion is performed in which the air-fuel ratio is higher than that of the stratified combustion but lower than the stoichiometric air-fuel ratio.

As described above, there are three regions where the air-fuel ratio greatly differs as the control region. When switching between these regions, the throttle valve opening degree is maintained while maintaining the same engine speed and engine torque. And the fuel injection amount must be changed to change the air-fuel ratio.

Therefore, the accelerator opening from the accelerator opening sensor 12 (the amount of depression of the accelerator pedal, corresponding to the engine load), the position signal from the crank angle sensor 13 for each unit crank angle, and the phase difference for each cylinder stroke From the reference signal (by measuring the number of position signals generated per unit time, or by measuring the reference signal generation cycle, the engine speed can be determined) from the idle switch (not shown). The control unit 11 calculates the target throttle valve opening degree TDTVO as follows so that a torque step does not occur before and after the switching of the target air-fuel ratio that changes according to the operating conditions. Throttle so that this target throttle valve opening TDTVO is obtained. Controlling the opening (specifically, JP-A-1
1-1182298). At this time, a signal from the throttle sensor 14 is also used as a feedback signal.

The total required opening area TTAAPO of the throttle valve portion is calculated according to the operating conditions.

A target basic volume flow ratio TQH0ST, which is a target volume flow ratio under a stoichiometric air-fuel ratio, is calculated from the total required opening area TTAAPO and the engine speed Ne.

By multiplying the target basic volume flow rate ratio TQH0ST by the maximum intake air amount MAXTP, a target basic intake air amount TTPST which is a target intake air amount at the stoichiometric air-fuel ratio is calculated.

By dividing the target basic intake air amount TTPST by the target equivalent ratio DML, a target intake air amount TTPGAS during operation at the target equivalent ratio is calculated.

This target intake air amount TTPGAS is divided by the maximum intake air amount MAXTP to calculate a target volume flow ratio TGQH0 during operation at a target equivalence ratio.

The target opening area TAGAS0 of the throttle valve 6 is calculated based on the target volume flow ratio TGQH0.

A target throttle valve opening TDTVO is calculated from the target opening area TAGAS0.

On the other hand, since the fuel injection device is of the D-Jetronic type, the signal of the actual intake pipe pressure from the pressure sensor 15 provided in the collector 2A of the intake passage 2 is an engine cooling water temperature signal from the water temperature sensor 16. , Oxygen sensor 1
Control unit 1 with oxygen concentration signal from 7
1, the control unit 11 calculates a fuel injection amount corresponding to cylinder intake based on the intake pipe pressure and the engine rotation speed in the same manner as in the conventional device, and multiplies this by a target equivalent ratio DML to obtain a target equivalent ratio. The fuel injection amount is calculated during operation in the DML and supplied to the engine from the fuel injection valve 4. For example, when using sequential injection,

[0041]

[Formula 1] Ti = Tp × DML × (α + αm−1) × 2 + Ts, where Tp: injection pulse width corresponding to cylinder intake, α: air-fuel ratio feedback correction coefficient, αm: air-fuel ratio learning value, Ts: invalid injection pulse width The fuel injection pulse width T given to the fuel injection valve 4 is given by the following equations:
i [ms] is calculated, and the fuel injection valve 4 is opened once during every two revolutions of the engine for a period of Ti in accordance with the ignition order of each cylinder.

In this case, the above target volume flow ratio TGQ
A one-time delay processing value Qc is calculated for H0 in consideration of a delay of the intake pipe pressure at the time of transition (acceleration or deceleration), and a delay processing of the intake pipe pressure detection value is performed on the one-time delay processing value Qc. Calculates the two-time delay processing value Qcav so that the phase becomes the same as the value (the signal corresponding to the conventional cylinder intake), and detects the intake pipe pressure by the ratio Qc / Qcav of the one-time processing value and the two-time processing value. The corrected value of the delay processing value is calculated as a predicted intake pipe pressure TMAP, and the predicted intake pipe pressure TMAP is used as a signal corresponding to cylinder intake to calculate the cylinder intake equivalent injection pulse width Tp of the above equation (1).

This will be further described with reference to FIG. 2, which shows a change during acceleration. When the throttle valve opening changes stepwise due to acceleration, the intake pipe pressure increases with a first-order delay, but the actual intake pipe pressure MAP detected by the pressure sensor 15 fluctuates under the influence of intake pulsation. (See the solid line in the middle part of FIG. 2), if the fuel injection amount is calculated using this signal as it is, the injection amount also fluctuates. Therefore, in the present invention, the influence of the intake air pulsation is given as follows. In addition, at the time of transition, an intake pipe pressure signal that does not delay or advance with respect to the phase of the actual intake pipe pressure MAP is generated.

<1> In order to remove the influence of intake pulsation from the actual intake pipe pressure MAP, a weighted average is calculated for the actual intake pipe pressure MAP to calculate a delay processing value MAPav of the intake pipe pressure (see the dashed line in the middle part of FIG. 2). .

<2> On the other hand, the target volume flow ratio TGQH0 is basically a value based on the throttle valve opening, and changes stepwise in accordance with the change in the throttle valve opening (see the solid line in the lower part of FIG. 2). , This target volume flow ratio TGQH
From the signal of 0, a signal that changes in the same phase as the phases of the actual intake pipe pressure MAP and the delay processing value MAPav of the intake pipe pressure is created. First, the actual intake pipe pressure MAP is calculated by calculating a delay processing value Qc of the target volume flow ratio using a time constant equivalent value when the delay of the intake pipe pressure is regarded as a first-order delay (see the lower broken line in FIG. 2). Is obtained. Further, the delay processing value MAPav of the intake pipe pressure is compared with Qc.
By calculating the delay processing value Qcav of Qc using the same time constant equivalent value as used in the calculation (see the dashed line in the lower part of FIG. 2), the signal having the same phase as the phase of the delay processing value MAPav of the intake pipe pressure is obtained. Get. These two values Qc, Qcav
Are delay processing values, Qc is defined as a one-time delay processing value of the target volume flow ratio, and Qcav is defined as a two-time delay processing value of the target volume flow ratio.

<3> Then, using the ratio Qc / Qcav of these two delay processing values,

[0047]

## EQU2 ## A value obtained by correcting the intake pipe pressure delay processing value MAPav by the equation TMAP = MAPav × (Qc / Qcav) is calculated as the predicted intake pipe pressure TMAP (see the broken line in the middle part of FIG. 2). Equation 2 shows that Qc / Qcav (>
1.0) as the correction magnification, the delay processing value MA of the intake pipe pressure.
The phase of Pav is advanced to the signal position of the actual intake pipe pressure MAP. That is, since Qc and Qcav are signals based on the accelerator opening, they are not affected by intake pulsation, and the influence of intake pulsation is also excluded from the intake pipe pressure delay processing value MAPav. Therefore, a predicted intake pipe pressure TMAP as an intake pipe pressure signal which is not affected by intake pulsation and has no delay or advance with respect to the phase of the actual intake pipe pressure MAP during a transition can be obtained by Expression 2.

In FIG. 2, the predicted intake pipe pressure T
If the MAP is superimposed on the actual intake pipe pressure MAP, it is difficult to see the MAP.

<4> Next, the predicted intake pipe pressure TMAP is used in the calculation of the fuel injection amount, but it is necessary to further consider the difference in the injection valve position and the injection method. Here, the following three cases are considered.

<A> When the fuel injection valve is provided at the intake port, and <B> When the fuel injection valve is provided facing the combustion chamber and the fuel is injected in the intake stroke (during homogeneous combustion), C> When fuel is injected in the compression stroke when the fuel injection valve is provided facing the combustion chamber (at the time of stratified combustion), in the case of <A>, the fuel is injected near the combustion chamber. Since a part of the fuel adheres to the intake port and the back of the intake valve umbrella to form wall-flow fuel, the air-fuel ratio leans to the lean side by the amount deprived of the wall-flow fuel during acceleration even if the fuel is increased with good response. Therefore, the pre-emption correction is performed on the one-time delay processing value Qc of the target volume flow ratio by the following equation (7) to obtain the pre-emption value T.
PT is calculated, and this is calculated as 1 of the target volume flow ratio of the above equation (2).
The expression replaced with the time delay processing value Qc,

[0051]

## EQU3 ## The predicted intake pipe pressure TMAP is calculated by the following equation: TMAP = MAPav × (TPT / Qcav). FIG. 3 shows the prefetch value TPT and the predicted intake pipe pressure TMAP in this case in comparison with FIG. 2 (see the two-dot chain line in the lower part of FIG. 3 for TPT and the broken line in the middle part of FIG. 3 for TMAP). Predicted intake pipe pressure TMAP (for <A>)
According to the estimated intake pipe pressure TMAP of FIG.
(In the case of <B>), it changes earlier, and the fuel is increased by the area of the difference. That is, the fuel corresponding to the area of the difference compensates for the increase of the wall flow fuel, whereby the acceleration (or deceleration) is performed even in the case of port injection.
Before and after the target value of the air-fuel ratio can be kept the same.

Next, in the case of the above <B>, since the supply of fuel is substantially simultaneous with the supply of intake air to the combustion chamber, the predicted intake pipe pressure TMAP of the above equation (2) may be used as it is. The case of the above <C> will be described later.

The contents of these controls executed by the control unit 11 will be described with reference to flowcharts.

FIG. 5 is for calculating the injection pulse width Tp corresponding to cylinder intake in the case of the above <A>, and is executed every 4 ms.

In step 1, the actual intake pipe pressure MAP, the engine speed Ne, the idle switch, and the target volume flow ratio TGQH0 are read. In the figure, the switch is set to "S
W ".

Here, the target volume flow ratio TGQH0 is a value obtained in the process of calculating the target throttle valve opening.
This will be described with reference to FIG.

A technique for finally calculating the target throttle valve opening while interposing the volume flow ratio in the middle of the calculation is known from Japanese Patent Application Laid-Open No. H11-182298.

In FIG. 6, the accelerator opening and the engine speed Ne are read in step 11 and a table having the contents shown in FIG.
O is calculated. In step 13, the required opening area AQSIS of the auxiliary air is added to the required opening area AAPO of the accelerator.
C is added to the total required opening area TTA of the throttle valve.
APO.

The required opening area AQSIS of the above auxiliary air
C is necessary to increase the idle rotation speed by a predetermined value when the compressor for an air conditioner is applied as a load to the engine output shaft during idling operation.

In the idle speed control, the required auxiliary air amount QSISC is predetermined based on the cooling water temperature, the elapsed time after the start, the battery voltage, the power steering switch, the air conditioner switch, the gear position in the case of a vehicle with an automatic transmission, and the like. The required auxiliary air amount QSISC is converted to a required auxiliary air opening area AQSISC using a predetermined table.

In step 14, the total required opening area TT
The AAPO is divided by the engine displacement VOL # and the engine speed Ne to obtain a total required opening area TGADNV per unit displacement and one engine speed. From this value TGADNV, a table containing the contents shown in FIG. By searching, the target basic volume flow ratio T
QH0ST (target volume flow ratio at stoichiometric air-fuel ratio) is calculated.

Note that a lower limiter (see FIG. 8) is provided for the engine speed Ne used in step 14 so that the denominator does not become zero.

In step 16, the maximum intake air amount MAXTP at the rotational speed at that time is obtained by searching a table containing the contents of FIG. 10 from the engine rotational speed Ne. By multiplying the volume flow ratio TQH0ST,
A target basic intake air amount (corresponding to a target torque at the stoichiometric air-fuel ratio) TTPST which is a target intake air amount at the stoichiometric air-fuel ratio is obtained.

Next, at step 18, the target basic intake air amount TTPST is divided by the target equivalent ratio DML to obtain a target intake air amount (intake amount when operating at the target equivalent ratio) TTPGAS. The target equivalence ratio DML is basically determined from the engine speed and the engine load. At this time, the target equivalence ratio DML is a value corresponding to the rotational speed when the target basic intake air amount is obtained.

There is a relationship between the target equivalence ratio DML and the target air-fuel ratio: DML = theoretical air-fuel ratio / target air-fuel ratio.
DML is 1.0 when operating at the stoichiometric air-fuel ratio as described later.
The value becomes smaller than 1.0 when stratified charge combustion in which the air-fuel ratio exceeds 40 or in lean combustion in which the homogeneous combustion and the air-fuel ratio are values such as 20 to 23. That is, at the time of stratified charge combustion or homogeneous lean burn, the intake air amount is increased as compared with the operation at the stoichiometric air-fuel ratio.

Although it is necessary to accurately determine the target intake air amount in consideration of the difference between the combustion efficiency at the stoichiometric air-fuel ratio and the combustion efficiency at the time of stratified combustion or homogeneous lean combustion, the target equivalent is simply described here. It is configured to simply divide by the ratio.

In step 19, the target intake air amount TTPG
A value obtained by dividing AS by the above-described maximum intake air amount MAXTP is calculated as a target volume flow rate ratio TGQH0, and this value TGQH
From 0 to step 20, a target opening area TDADNV per unit displacement of the throttle valve and per rotation speed is calculated by searching a table having the contents shown in FIG.

In step 21, the calculated TDADN is calculated.
V is multiplied by the engine rotation speed Ne and the displacement VOL # to obtain a target opening area TAGAS0 of the throttle valve, and the target throttle valve is searched by searching the table having the contents shown in FIG. The opening degree TDTVO is calculated. This target throttle valve opening TDTVO is given to the throttle valve control device 7 as a control amount, and the throttle valve 6 is driven so as to have the target throttle valve opening.

Since the target throttle valve opening is calculated as described above, the target volume flow ratio TG obtained during the calculation is calculated.
QH0 (step 19 in FIG. 6) is read in step 1 in FIG.

In step 2 in FIG. 5, the idle switch is checked. When the idle switch is OFF (at the time of non-idle), the process proceeds to step 3 and subsequent steps. In step 3

[0071]

## EQU4 ## MAPav = MAP × DP + MAPavn ₋₁ ×
(1-DP), where MAPav: intake pipe pressure delay processing value, DP: weighted average coefficient, MAPav _n-1 : previous value of MAPav, and calculates intake pipe pressure delay processing value MAPav. This is the actual intake pipe pressure MAP which is a sensor detection value.
(See the solid line in the middle part of FIG. 3) fluctuates under the influence of the intake pulsation, so that the influence is removed to obtain a smooth signal (see the one-dot chain line in the middle part of FIG. 3). Therefore, the weighted average coefficient DP may be set to such an extent that the pulsation on the signal of the actual intake pipe pressure MAP can be eliminated.

In step 4,

[0073]

## EQU5 ## Qc = TGQH0 × Flood4 + Qc _n−1 ×
(1-Flood4), where Qc is the one-time delay processing value of the target volume flow ratio, Flood4 is the weighted average coefficient, Qcn _{-1 is} the previous value of the Qc, and the one-time delay processing value of the target volume flow ratio. Calculate Qc.

Here, the weighted average coefficient Fload of equation (5)
4 is a time constant equivalent value when the delay in the intake pipe pressure is regarded as a first-order delay. Therefore, this target volume flow ratio of 1
The time delay processing value Qc changes in the same phase as the phase of the actual intake pipe pressure MAP (see the lower broken line in FIG. 3).

Since the time constant when the delay in the intake pipe pressure is regarded as a first-order delay increases as the intake pipe volume increases, the weighted average coefficient Fl having a reciprocal relationship with this time constant is obtained.
oad4 is a value that decreases as the intake pipe volume increases. In addition, since the delay of the intake pipe pressure changes according to the operating conditions (load, engine speed), FIG. 13 is shown from the target volume flow ratio TGQH0 (or accelerator opening) as the engine load and the engine speed Ne. It is conceivable that the calculation is performed by searching for a map.

In step 5 of FIG.

[0077]

Qcav = Qc × DP + Qcav _n−1 × (1−DP), where Qcav: a twice-processed value of intake pipe pressure, DP: weighted average coefficient, Qcav _n−1 : previous value of Qcav A two-time delay processing value Qcav of the intake pipe pressure is calculated by the equation. The two-time delay processing value Qcav of the target volume flow ratio changes in the same phase as the phase of the delay processing value MAPav of the intake pipe pressure (see the dashed line in the lower part of FIG. 3).

In step 6,

[0079]

## EQU7 ## TPT = Qc + (TGQH0-Qc) × Flo
The prefetch value TPT is calculated by performing a prefetch correction on the one-time delay processing value Qc of the target volume flow ratio by the formula of ad4 × 2.5.

This prefetch correction will be described with reference to FIG.
FIG. 4 shows a waveform of the volume flow ratio at the time of acceleration. Since it can be regarded as a change in intake air, it will be described below as intake air. In the case of port injection, experiments have shown that
The fuel reaches the cylinder with a delay of ms. On the other hand, the cylinder intake increases according to Qc from the timing of t1. Therefore, when the fuel amount injected at t1 is calculated with respect to the cylinder intake amount Qc1 at t1, when the calculated fuel amount reaches the cylinder at t2 after 10 ms, it does not correspond to the cylinder intake amount at that time. . This is because the cylinder intake air amount at t2 10 ms after t1 is Qc2. Therefore, the injection amount at t1 is Qc
It must correspond to 2. Similarly, t3
Must be one corresponding to Qc3. Thus, the cylinder intake amount used to calculate the injection amount has a TPT waveform.

In order to generate the TPT waveform shown by the two-dot chain line, Qc shown by the broken line is advanced by 10 ms in time. Since the calculation timing is every 4 ms, t1
The change amount of Qc after 4 ms with reference to (TGQH0−
Qc) × Flood4, so this is 10/4 (=
2.5) If it is multiplied, Qc is 10 even in the calculation every 4 ms.
The time can be advanced by ms. That is, Q
(TGQH0-Qc) × Flood4 × 2.
By adding 5 as a preemption correction value, a preemption value TPT of Qc (= Qc + preemption correction value) can be obtained.

Returning to FIG. 5, in step 7, the predicted intake pipe pressure TMAP is calculated from the above equation (3), and the cylinder containing the cylinder shown in FIG. 14 is searched from the predicted intake pipe pressure TMAP and the engine speed Ne. The injection pulse width Tp [ms] is calculated. This Tp gives a fuel injection amount that can obtain a mixture with a target equivalent ratio DML corresponding to cylinder intake.

On the other hand, when the idle switch is ON (idle), the process proceeds to steps 9 and 10, and a value (for example, a constant value) corresponding to the intake pipe pressure at the time of idling is set to the intake pipe pressure delay processing value MAPav. . This is because the intake pipe pressure during idling is used as the initial value of the intake pipe pressure delay processing value MAPav. Also, the target volume flow ratio TGQH
0 is set in the one-time delay processing value Qc and the two-time delay processing value Qcav of the target volume flow ratio. This also results in a one-time delay processing value Qc and a two-time delay processing value Qca of TGQH0 (map value).
This is for setting the initial value of v.

At step 10, after the intake pipe pressure delay processing value MAPav is directly used as the predicted intake pipe pressure TMAP, the processing at step 8 is executed.

The cylinder-injection-equivalent injection pulse width Tp calculated in this manner is determined by a fuel injection control routine (not shown) when, for example, sequential injection is performed.
The fuel injection pulse width Ti [ms] to be given to the fuel injection valve 4 is calculated by the above equation (1), and once every two engine revolutions, the fuel injection valve 4 for the period of Ti in accordance with the ignition order for each cylinder.
Is opened.

The flowchart of FIG. 15 is a second embodiment, which replaces FIG. 5 of the first embodiment. FIG.
The same step numbers are assigned to the same parts as. Second
The embodiment corresponds to the case of the above <B> (the case of direct injection into the combustion chamber in the intake stroke).

In the case of <B>, since the supply of fuel is substantially simultaneous with the supply of air to the combustion chamber, the predicted intake pipe pressure TMAP of the above equation (2) may be used as it is.
There is no need to calculate a prefetch value (step 2 in FIG. 15).
1).

As described above, in the second embodiment, the target volume flow ratio TGQH of the throttle valve portion is determined based on the accelerator opening.
0, and a one-time delay processing value Qc is calculated for the volume flow ratio TGQH0 in consideration of the delay of the intake pipe pressure at the time of transition, and the actual intake pipe pressure M is calculated for this one-time delay processing value Qc.
The two-time delay processing value Qcav is calculated so that the phase becomes the same as the AP delay processing value MAPav, and the actual intake pipe pressure (intake pipe pressure) is calculated by the ratio Qc / Qcav of the one-time delay processing value and the two-time delay processing value. Since the value obtained by correcting the delay processing value MAPav of the detected value) is calculated as a predicted intake pipe pressure TMAP (a signal corresponding to cylinder intake), the predicted intake pipe pressure TMAP is calculated.
According to according to the influence of the intake pulsation does not fluctuate,
In addition, when the vehicle is accelerating or decelerating, the signal becomes an ideal cylinder intake equivalent signal in the D-Jetronic system which does not delay or advance with respect to the phase of the actual cylinder intake equivalent signal. Based on the predicted intake pipe pressure TMAP, the cylinder intake equivalent injection is performed. By calculating the pulse width Tp, the air-fuel ratio can be maintained at the target before and after acceleration or deceleration in the case of the above <B>, that is, when directly injecting into the combustion chamber during the intake stroke (during homogeneous combustion).

In the case of the above <A>, that is, when the fuel injection valve is at the intake port, the fuel wall flow becomes a problem, and the air-fuel ratio deviates from the target value to the lean side at the initial stage of acceleration, causing hesitation or exhaust gas. According to the first embodiment, the performance is deteriorated. However, according to the first embodiment, the prefetch correction is performed on the one-time delay processing value Qc to obtain the prefetch value Tc.
PT is calculated, and the prefetch value TPT is delayed by one time and the processed value Q
The value obtained by correcting the delay processing value MAPav of the actual intake pipe pressure (detected intake pipe pressure value) with the ratio TPT / Qcav used in place of c is calculated as the predicted intake pipe pressure TMAP. It is possible to supply a larger amount of fuel by the difference of the round delay processing value Qc, so that even in the case of intake port injection, the air-fuel ratio does not become lean at the initial stage of acceleration, and the responsiveness and exhaust performance at the initial stage of acceleration are increased. Is improved.

The flowchart of FIG. 16 is a third embodiment, which is a replacement for FIG. 15 of the second embodiment. The same steps as those in FIG. 15 are denoted by the same step numbers.
The third embodiment corresponds to the case <C> (in the case where the fuel is directly injected into the combustion chamber during the compression intake stroke).
The difference from FIG. 15 of the embodiment is that the injection pulse width corresponding to the cylinder intake corresponding to the cylinder intake of the second embodiment is given the dead time corresponding to the cylinder intake corresponding to the third embodiment (step). 31-33).

This will be described with reference to FIG.
Injection pulse width Tp corresponding to cylinder intake in case of <B> above
Has a waveform substantially in phase with the predicted intake pipe pressure TMAP (see the solid line at the bottom of FIG. 17). In this case, since Tp can be regarded as the same as the fuel amount, FIG.

In the case of the above <C>, the fuel injection is delayed approximately 10 ms with respect to the cylinder intake in accordance with the delay of the injection timing from the intake stroke to the compression stroke. At the timing of tb, the fuel amount Tpa at ta is similarly set at 10 m from tb.
At tc after s, it is necessary to give the fuel amount Tpb at tb. From this, it can be seen that in the case of <C>, the waveform of the injection pulse width Tp corresponding to cylinder intake in the case of <B> may be temporally delayed by 10 ms. Therefore, the cylinder-injection-equivalent injection pulse width Tp in the case of <B> is set again to Tp0 in the third embodiment, and a waveform obtained by delaying this by 10 ms in time is the cylinder-injection-equivalent injection pulse width Tp of <C>. (See the dashed line at the bottom of FIG. 17).

Returning to FIG. 16, mainly the differences from the second embodiment will be described. In step 31, the value of the memory is shifted. The memories TP <b> 0 and TP <b> 1 store the current calculated value of the cylinder intake equivalent injection pulse width in the case of <B>.
Memory TP1, 2 for storing the operation value of the previous time (4 ms before)
Memory TP2, TP3 for storing the operation value before (8 ms before)
Since the memory TP3 for storing the operation value of the previous time (12 ms before) is provided, the values of the memories TP2, TP1, and TP0 are transferred to the memories TP3, TP2, and TP1, respectively. In step 32, the cylinder-injection-equivalent injection pulse width obtained by searching the map shown in FIG. 14 from the predicted intake pipe pressure TMAP and the engine rotation speed Ne is stored in the memory TP0 as the current calculation value.

In step 33, the values of the memories TP2 and TP3 are read, and the average value is set as the current cylinder-injection-equivalent injection pulse width Tp. This is the value 8 ms before and 12 m
The value before 10 ms is approximated by linear interpolation using the value before s.

As described above, according to the third embodiment, in the case of the above <C>, that is, when the fuel is directly injected into the combustion chamber in the compression stroke (at the time of stratified combustion), the air-fuel ratio before and after acceleration or deceleration is increased. You can keep on your goals.

In the system in which fuel is directly injected into the combustion chamber, there are a stratified combustion region and a homogeneous combustion region.
It goes without saying that FIGS. 15 and 16 are used in combination.

The predicted intake pipe pressure TMAP of the embodiment is D-
This signal is equivalent to cylinder intake in the JETRONIC system. In the embodiment, the description has been given of the case of an engine equipped with a D-JETRONIC fuel injection device. However, the present invention is not limited to this. Can be applied to an engine equipped with a so-called L-jetronic type fuel injection device that calculates a fuel injection amount corresponding to cylinder intake based on an output of an air flow meter that detects the fuel injection amount. To explain this, for example,
Referring to JP-A-290949, a fuel injection amount corresponding to cylinder intake is calculated as follows.

I) Based on the intake air flow rate Qa obtained by converting the output of the air flow meter into air flow rate units and the engine speed Ne.

[0099]

[Mathematical formula-see original document] Tp0 = (Qa / Ne) * K, where K is a constant, and the basic injection pulse width before smoothing Tp0 [ms] is calculated.

Ii) Since the detection value of the air flow meter for detecting the mass flow rate at the position upstream of the throttle valve also fluctuates under the influence of the intake pulsation, the basic injection pulse width before smoothing is used to remove the influence of the intake pulsation from the air flow meter output. Tp0
And a delay processing value is obtained as a basic injection pulse width Tp [ms].

Iii) Even if the intake air at the position of the air flow meter changes stepwise during transition, the cylinder intake changes with a delay due to the presence of the intake pipe volume.

[0102]

## EQU9 ## Avtp = Tp × Load + Avtp _n−1 ×
(1−Load), where Fload: weighted average coefficient, Avtp _n−1 : previous value of Avtp, and the injection pulse width Avtp [m
s].

Iv) And, for example, when it is a sequential injection,

[0104]

## EQU10 ## Ti = Avtp × DML × (α + αm−1)
× 2 + Ts, where Tp: cylinder-injection-equivalent injection pulse width, α: air-fuel ratio feedback correction coefficient, αm: air-fuel ratio learning value, Ts: invalid injection pulse width T
Compute i [ms].

Here, Avtp in Expression 9 is a signal of the fuel injection amount corresponding to the cylinder intake amount. Note that the same symbol (Tp) as in the D-Jetronic system is partially used,
The contents are different from the D-Jetronic method. The weighted average coefficient Fload of the equation 9 is a time constant equivalent value when a delay at the time of transition due to the presence of the intake pipe volume is regarded as a first-order delay, and the weighted average coefficient Fload4 in the D-jetronic method is The content is different.

Now, also in the L-Jetronic system, a delay process is performed in the above ii) in order to remove the influence of the intake pulsation. By associating with Equation 4 of the embodiment in the D-Jetronic system,

[0107]

[Mathematical formula-see original document] Tp = Tp0 * DP + Tpn _-1 * (1-DP), where Tp: delay processing value of Tp0 (= basic injection pulse width), DP: weighted average coefficient, Tpn _-1 : last time of Tp Where the value is FIG. 18 shows the case of the L-Jetronic system so as to facilitate comparison with the D-Jetronic system (FIG. 2). The delay process using the weighted average coefficient Fload of the basic injection pulse width Tp0 before smoothing is shown. The value (refer to the middle solid line in FIG. 18) corresponds to the actual intake pipe pressure MAP in the D-Jetronic system, and the cylinder intake equivalent injection pulse width Avtp (FIG. 18) which is a delay processing value of the basic injection pulse width Tp in Expression 11 (See the dot-dash line in the middle)
Corresponds to the intake pipe pressure delay processing value MAPav in the D-Jetronic system.

Therefore, in the L-Jetronic system, in the case of the above <B>,

[0109]

## EQU12 ## TAvtp = Avtp × (Qc / Qca)
v) Predicted cylinder intake-equivalent injection pulse width TAvt by the following equations:
p (see the middle broken line in FIG. 18), and in the case of <A> (port injection),

[0110]

[Expression 13] TAvtp = Avtp × (TPT / Qca
v) Predicted cylinder intake-equivalent injection pulse width TAvt by the following equations:
p is calculated, and TAvtp may be used instead of the conventional Avtp in the above equation (10).

As described above, in the L-Jetronic system, the pre-smoothing basic injection pulse width Tp0 is calculated based on the detected value of the mass flow rate upstream of the throttle valve, and the intake pulsation is calculated with respect to the pre-smoothing basic injection pulse width Tp0. The basic injection pulse width Tp is calculated by performing a delay processing value in consideration of the above, and a delay processing value in consideration of a transitional delay due to the presence of the intake pipe volume is performed on the basic injection pulse width Tp to obtain a cylinder intake equivalent. The injection pulse width Avtp is calculated. In this case, the volume flow ratio TGQH0 of the throttle valve portion is calculated based on the accelerator opening, and this volume flow ratio TGQH0 is calculated.
, A one-time delay processing value Qc taking into account the delay of the intake pipe pressure during transition is calculated, and the basic injection which is a delay processing value of the pre-smoothing basic injection pulse width Tp0 is calculated with respect to the one-time delay processing value Qc. The two-time delay processing value Qcav is calculated so that the phase becomes the same as the pulse width Tp, and these one-time delay processing value and
By calculating, as a predicted cylinder intake equivalent injection pulse width TAvtp, a value obtained by correcting the cylinder intake equivalent injection pulse width Avtp with the time delay processing value ratio Qc / Qcav, the TAvtp varies under the influence of intake pulsation. In addition, when accelerating or decelerating, there is no delay or advance with respect to the phase of the actual fuel injection amount corresponding to the actual cylinder intake (see the middle solid line in FIG. 18). This gives the fuel injection amount (see the middle broken line in FIG. 18), whereby before and after acceleration and deceleration in the case of the above <B>, that is, when directly injecting into the combustion chamber in the intake stroke (during homogeneous combustion). The air-fuel ratio can be maintained at the target.

Also, a pre-correction is performed on the one-time delay processing value Qc to calculate a pre-processing value TPT, and the ratio TP is used instead of the pre-processing value TPT instead of the one-time processing value Qc.
The injection pulse width Av corresponding to the cylinder intake is obtained by T / Qcav.
By calculating the corrected value of tp as the predicted cylinder intake equivalent injection pulse width TAvtp, the prefetch value TPT and 1 are calculated.
It is possible to supply a larger amount of fuel by the difference of the round delay processing value Qc, so that even in the case of intake port injection, the air-fuel ratio does not become lean at the initial stage of acceleration, and the responsiveness and exhaust performance at the initial stage of acceleration are increased. Is improved.

Here, in the L-Jetronic system, the fuel injection amount (Avtp, TAvtp) corresponding to the cylinder intake is directly calculated without calculating the cylinder intake amount, but the cylinder intake amount is calculated. It goes without saying that the fuel injection amount corresponding to the cylinder intake may be calculated later.

In the embodiment, the description has been given of the case where the prefetch value TPT is calculated in the case of the port injection. However, the prefetch value TPT may not be calculated.

In the embodiment, the case where the target volume flow ratio is adopted as the volume flow ratio has been described. However, the actual volume flow ratio can be determined by searching a predetermined map from the detected value of the throttle valve opening and the engine speed Ne. It is also possible to calculate and use this volume flow ratio. Further, the volume flow rate is not limited to the volume flow rate ratio, and may be a volume flow rate which is a value for each engine obtained by multiplying the volume flow rate by the displacement VOL #.

By the way, the weighted average coefficient Fload4, which is a value equivalent to a time constant when the above-described delay in the intake pipe pressure is regarded as a first-order delay, matches the reference throttle valve when there is no mounting error. If the throttle valve is slightly open or close than the reference throttle valve used for matching due to the installation error of the throttle valve, the weighted average coefficient Fload4 does not match,
An error occurs in the one-time delay processing value Qc of the target volume flow ratio, and the calculation accuracy of the predicted intake pipe pressure TMAP and the cylinder intake equivalent injection pulse width Tp in the D-jetronic system and the predicted cylinder intake in the L-jetronic system are reduced accordingly. The calculation accuracy of the equivalent injection pulse width TAvtp decreases. For this reason, it is known to introduce a learning function corresponding to a throttle valve installation error (Japanese Patent Laid-Open No. 1-290).
U.S. Pat. No. 949), and it is desirable to introduce a learning function corresponding to a throttle valve mounting error in the present invention by utilizing this.

It should be noted that the technology disclosed in this publication will be briefly described. This technology includes an L-jetronic type fuel injection device, in which a throttle valve is mechanically linked with an accelerator pedal, and is not used. Since the target value of the fuel ratio is the stoichiometric air-fuel ratio in the entire operation range, the volume flow ratio QH at the stoichiometric air-fuel ratio based on the throttle valve opening and the engine speed detected by the throttle sensor is used.
0 is calculated. In this case, the technology disclosed in the publication discloses L
Calculating a basic injection pulse width Tp (Tp of the above ii) in order to provide a jetronic fuel injection device;
Since the basic injection pulse width Tp and the volume flow ratio QH0 are proportional to the total performance of the engine, if the learning value of the throttle valve opening is updated so that the ratio between the two attains a target value in a steady state (for example, during idling). In addition, it is possible to absorb a mounting error of the throttle valve and a detection error of the throttle sensor. That is, according to the value obtained by correcting the throttle valve opening with the learning value of the throttle valve opening, the volume flow ratio QH0 can be calculated with the same accuracy as when there is no throttle valve installation error or throttle sensor detection error.

[Brief description of the drawings]

FIG. 1 is a control system diagram of a first embodiment.

FIG. 2 is a waveform chart for explaining an operation at the time of acceleration according to a second embodiment.

FIG. 3 is a waveform chart for explaining the operation of the first embodiment during acceleration.

FIG. 4 is a preliminary value T of a one-time delay processing value of a target volume flow ratio.
FIG. 4 is a waveform chart for explaining a method of calculating PT.

FIG. 5 is a flowchart for explaining the calculation of a cylinder intake equivalent injection pulse width according to the first embodiment;

FIG. 6 is a flowchart for explaining calculation of a target throttle valve opening.

FIG. 7 is a characteristic diagram showing a relationship between an accelerator opening and a required opening area of an accelerator of a throttle valve.

FIG. 8 is a characteristic diagram of a lower limiter of an engine rotation speed.

FIG. 9 is a characteristic diagram showing a relationship between a total required opening area per unit displacement and per rotation speed and a target basic volume flow ratio.

FIG. 10 is a characteristic diagram illustrating a relationship between a rotation speed and a maximum intake air amount.

FIG. 11 is a characteristic diagram showing a relationship between a target volume flow ratio and a target opening area per unit displacement and one rotation speed of a throttle valve.

FIG. 12 is a characteristic diagram showing a relationship between a target opening area and a target throttle valve opening.

FIG. 13 is a characteristic diagram of a weighted average coefficient which is a value equivalent to a time constant when a delay in intake pipe pressure is regarded as a first-order delay.

FIG. 14 is a characteristic diagram of a cylinder intake equivalent injection pulse width.

FIG. 15 is a flowchart for explaining a calculation of a cylinder intake equivalent injection pulse width according to the second embodiment.

FIG. 16 is a flowchart for explaining a calculation of a cylinder intake equivalent injection pulse width according to the third embodiment;

FIG. 17 is a waveform chart for explaining the operation of the third embodiment during acceleration.

FIG. 18 is a waveform chart for explaining an operation at the time of acceleration in the case of the L-Jetronic method.

FIG. 19 is a waveform chart for explaining the operation of the conventional device during acceleration.

FIG. 20 is a diagram corresponding to claims of the first invention.

FIG. 21 is a diagram corresponding to claims of the second invention.

FIG. 22 is a diagram corresponding to claims of the fifth invention.

FIG. 23 is a view corresponding to claims of the sixth invention.

[Explanation of symbols]

 4 Fuel Injection Valve 6 Throttle Valve 7 Throttle Valve Controller 11 Control Unit 15 Pressure Sensor

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F02D 45/00364 F02D 45/00 364G 376 376B 41/02 330 41/02 330A 41/04 330 41/04 330B F-term (reference) 3G084 AA04 BA09 BA13 CA03 CA04 CA06 DA05 DA21 EA01 EA05 EA07 EA08 EB08 EB12 EB17 EB25 EC03 FA07 FA10 FA11 FA29 FA33 FA38 3G301 HA04 HA16 JA11 JA13 JA14 JA17 JA29 KA08 MA04 MA03 MA03 LC04 NA06 NB02 NB05 NB07 NB18 NC01 NC02 ND02 ND21 NE14 NE15 NE19 NE23 PA01Z PA07Z PA11A PA11Z PA14Z PD03A PE01Z PE03Z PE08Z PF03Z PF08Z PF13Z PF14Z PF16Z

Claims (12)

[Claims] A means for detecting an intake pipe pressure; a means for calculating a delay processing value of the detected value; a means for calculating a volume flow rate of a throttle valve based on an accelerator opening or a throttle valve opening; Means for calculating a one-time delay processing value in consideration of the delay of the intake pipe pressure at the time of transient with respect to the volume flow rate; and the detection processing value has the same phase as the one-time delay processing value for the one-time delay processing value. Means for calculating the twice-delayed processing value, and means for calculating, as a signal corresponding to cylinder intake, a value obtained by correcting the delayed processing value of the detection value by the ratio of the one-time delayed processing value and the two-times delayed processing value. An intake air amount detection device for an engine, comprising: Means for detecting a mass flow rate upstream of the throttle valve; means for calculating a delay processing value in consideration of intake pulsation with respect to the detected value; Means for calculating a delay processing value in consideration of the accompanying transitional delay; means for calculating the volume flow rate of the throttle valve section based on the accelerator opening or throttle valve opening; Means for calculating a one-time delay processing value taking into account the pipe pressure delay; and a two-time delay processing value corresponding to the one-time delay processing value so as to have the same phase as the delay processing value taking the intake pulsation into consideration. Means for calculating, and calculating, as a signal of the cylinder intake air amount, a value obtained by correcting a delay processing value in consideration of a transitional delay caused by the presence of the intake pipe volume by a ratio of the one-time processing value and the two-time processing value. Means for performing Intake air amount detecting device for an engine characterized and. 3. The intake air amount detecting device for an engine according to claim 1, wherein a volume flow rate ratio is used instead of the volume flow rate. 4. The intake air amount detecting device for an engine according to claim 1, further comprising a learning function corresponding to a throttle valve mounting error with respect to the throttle valve opening. 5. A means for detecting an intake pipe pressure, a means for calculating a delay processing value of the detected value, a means for calculating a volume flow rate of a throttle valve section based on an accelerator opening or a throttle valve opening, Means for calculating a one-time delay processing value in consideration of the delay of the intake pipe pressure at the time of transient with respect to this volume flow rate; Means for calculating the twice-delayed processing value, and means for calculating, as a signal corresponding to cylinder intake, a value obtained by correcting the delayed processing value of the detection value by the ratio of the one-time delayed processing value and the two-times delayed processing value. An engine fuel injection amount control device comprising: means for calculating a fuel injection amount based on the signal; and means for supplying the fuel of the injection amount to the engine. 6. A means for detecting a mass flow rate upstream of a throttle valve, a means for calculating a delay processing value in consideration of intake pulsation with respect to the detected value, and a means for determining the presence of an intake pipe volume with respect to the delay processing value. Means for calculating a delay processing value in consideration of the accompanying transitional delay; means for calculating the volume flow rate of the throttle valve section based on the accelerator opening or throttle valve opening; Means for calculating a one-time delay processing value taking into account the pipe pressure delay; and a two-time delay processing value corresponding to the one-time delay processing value so as to have the same phase as the delay processing value taking into account the intake pulsation. Means for calculating, and calculating, as a signal of the cylinder intake air amount, a value obtained by correcting a delay processing value in consideration of a transitional delay caused by the presence of the intake pipe volume by a ratio of the one-time processing value and the two-time processing value. Means to do this A fuel injection amount control device for an engine, comprising: means for calculating a fuel injection amount based on a signal; and means for supplying the fuel of the injection amount to the engine. 7. The fuel injection amount control device for an engine according to claim 5, wherein a volume flow ratio is used instead of the volume flow rate. 8. The fuel injection amount control device for an engine according to claim 5, further comprising a learning function corresponding to a throttle valve mounting error with respect to the throttle valve opening. 9. When the means for supplying fuel is provided in the intake port section, a prefetch value obtained by performing prefetch correction on the one-time delay processing value is calculated, and this prefetch value is calculated by the one-time processing. The engine fuel injection amount control device according to claim 5, wherein a value obtained by correcting the delay processing value of the detected value with the ratio used in place of the delay processing value is calculated as a signal corresponding to cylinder intake. 10. When the means for supplying fuel is provided in an intake port section, a prefetch value obtained by preliminarily correcting the one-time delay processing value is calculated, and the prefetch value is calculated by the one-time processing. 7. The fuel injection amount control device for an engine according to claim 6, wherein a value obtained by correcting the delay processing value of the detection value with the ratio used instead of the delay processing value is calculated as a signal of a cylinder intake amount. 11. The prefetch value is determined according to a difference between a volume flow rate of the throttle valve section and a one-time delay processing value thereof, and a value corresponding to a time constant when a delay in intake pipe pressure during the transition is regarded as a first-order delay. 11. A value obtained by adding a prefetch correction value to the one-time delay processing value.
3. The fuel injection amount control device for an engine according to claim 1. 12. When the fuel supply means is provided facing the combustion chamber and the fuel is injected in the compression stroke, the injection timing is delayed from the intake stroke to the compression stroke with respect to the fuel injection amount signal. 7. The fuel injection amount control device for an engine according to claim 5, wherein a dead time is given.