JP2000213401A - Atmospheric pressure detecting apparatus for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To conduct atmospheric pressure detection even in medium or low load operational state of an internal combustion engine, and to reduce error between obtained atmospheric pressure and present atmospheric pressure. SOLUTION: Intake air pressure or atmospheric pressure is introduced into a back pressure chamber of a pressure control valve 30, resulting in generating differential pressure in fuel pressure on an fuel injection valve 5 based on difference between the intake air pressure and the atmospheric pressure. The differential pressure emerges as the change of a fuel injection amount from the fuel injection valve, and is calculated as an air-fuel ratio F/B(feed back) correction coefficient based on each output from an air-fuel ratio sensor 12. Thereby, the intake air pressure sensed by an intake air sensor 11, the air-fuel ratio F/B correction coefficient, and set pressure of the pressure control valve 30 are found, so that the atmospheric air pressure is calculated. Accordingly, the atmospheric air pressure of an internal combustion engine 1 is calculated not only in a conventional high load operational state but also in a medium or low operational state. Error between the atmospheric pressure obtained by atmospheric pressure detection processing and the present atmospheric pressure is reduced to improve reliability.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an atmospheric pressure detecting device for detecting an atmospheric pressure during operation of an internal combustion engine.

[0002]

2. Description of the Related Art Conventionally, in an atmospheric pressure detecting device for an internal combustion engine which does not have a dedicated sensor for detecting the atmospheric pressure, a throttle valve disposed in an intake passage of the internal combustion engine is fully opened and an intake valve on a downstream side thereof is provided. Atmospheric pressure detection is performed by an estimation calculation process based on an output signal from a load sensor such as an intake pressure by an intake pressure sensor or an intake air amount by an intake air amount sensor in a high-load operation state in which the atmospheric pressure is equal to the atmospheric pressure. It has been known.

[0003]

However, in the above-described apparatus, the frequency of occurrence of a high-load operation state, which is an execution condition of the atmospheric pressure detection, is low, so that the atmospheric pressure obtained by the atmospheric pressure detection processing and the current atmospheric pressure are compared. There was a problem that the error with the atmospheric pressure became large.

Therefore, the present invention has been made to solve such a problem, and enables the detection of the atmospheric pressure not only in the high load operation state of the internal combustion engine but also in the medium / low load operation state. Increase the frequency of execution conditions,
It is an object of the present invention to provide an atmospheric pressure detecting device for an internal combustion engine that can reduce an error between the atmospheric pressure obtained by the atmospheric pressure detecting process and the current atmospheric pressure.

[0005]

According to the atmospheric pressure detecting device for an internal combustion engine of the first aspect, the intake pressure calculated or estimated by the intake pressure calculating means based on the output from the load sensor in the back pressure chamber of the pressure control valve. By introducing atmospheric pressure, or atmospheric pressure,
The fuel pressure applied to the fuel injection valve generates a pressure difference (pressure difference) based on the difference between the intake pressure and the atmospheric pressure. This differential pressure appears as a change in the amount of fuel injected from the fuel injection valve, and is calculated by the related value calculating means as an air-fuel ratio related value which is a value related to the air-fuel ratio based on each output from the air-fuel ratio sensor. The rate of increase in the amount of fuel injection from the fuel injection valve, which is the rate of increase in the amount of fuel injection from the fuel injection valve, is calculated by the rate-of-increase calculating means based on the ratio of the air-fuel ratio-related values. Is calculated by the change rate calculating means. In this manner, the atmospheric pressure is calculated by the atmospheric pressure calculating means by knowing the differential pressure change rate, the intake pressure and the set pressure of the pressure control valve. Therefore, the atmospheric pressure can be calculated not only in the high load operation state of the internal combustion engine but also in the medium / low load operation state, and the error between the atmospheric pressure obtained by the atmospheric pressure detection processing and the current atmospheric pressure can be reduced.
Thereby, the reliability of the atmospheric pressure by the atmospheric pressure detection processing can be improved.

According to the second aspect of the present invention, the atmospheric pressure is introduced into the back pressure chamber of the pressure control valve and is calculated or estimated by the intake pressure calculating means based on the output from the load sensor. The intake pressure in the first operating state and the intake pressure in the second operating state where the intake pressure is different are calculated. The difference between the pressure difference before and after the fuel injection valve in the first operating state and the second operating state in which the intake pressure is different appears as a change in the fuel injection amount, and is a value related to the air-fuel ratio based on each output from the air-fuel ratio sensor. Is calculated by the related value calculation means as the air-fuel ratio related value. Here, the fuel injection amount is corrected by the differential pressure correcting means according to the magnitude of the differential pressure applied to the fuel injection valve. The rate of increase in the amount of fuel injection from the fuel injection valve, which is the rate of increase in the amount of fuel injection from the fuel injection valve, is calculated by the rate-of-increase calculating means based on the ratio of the air-fuel ratio-related values. Is calculated by the change rate calculating means. In this way, the atmospheric pressure is calculated by the atmospheric pressure calculating means by knowing the differential pressure change rate, the intake pressure in the first operating state and the set pressure of the pressure control valve in the second operating state. Therefore, the atmospheric pressure can be calculated not only in the high load operation state of the internal combustion engine but also in the medium / low load operation state, and the error between the atmospheric pressure obtained by the atmospheric pressure detection processing and the current atmospheric pressure can be reduced. Thereby, the reliability of the atmospheric pressure by the atmospheric pressure detection processing can be improved.

The air-fuel ratio related value in the atmospheric pressure detecting device for an internal combustion engine according to claim 3 is an air-fuel ratio feedback correction coefficient for correcting the fuel injection amount so that the air-fuel ratio or the air-fuel ratio becomes the target air-fuel ratio. It is calculated based on the output from the air-fuel ratio sensor when the fuel ratio control is executed. For this reason, it is not necessary to add a new sensor or the like, so that a system with high reliability of the atmospheric pressure by the atmospheric pressure detecting process can be constructed without increasing the cost.

In the atmospheric pressure detecting device for an internal combustion engine according to the fourth aspect, the fuel injection amount is corrected by the differential pressure correcting means according to the magnitude of the differential pressure applied to the fuel injection valve. The correction process is stopped during the detection period of the intake pressure and the air-fuel ratio related value in the operation state of the above, so that the intake pressure and the air-fuel ratio related value can be stably obtained without being affected by the correction. . This allows
The reliability of the atmospheric pressure by the atmospheric pressure detection processing can be improved.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on examples.

Embodiment 1 FIG. 1 is a schematic diagram showing an entire configuration of an atmospheric pressure detecting device for an internal combustion engine according to a first embodiment of the present invention. FIG. 2 is a schematic diagram showing the internal configuration of the pressure control valve used in FIG.

In FIG. 1, an internal combustion engine 1 is of a four-cylinder, four-cycle, spark ignition type, and its intake air passes from an upstream side through an air cleaner 2, an intake passage 3, and a throttle valve 4 to be fueled in the intake passage 3. Injector (injector) 5
Is mixed with the fuel injected from the intake port and is distributed and supplied into each cylinder from the intake port 6 as an air-fuel mixture having a predetermined air-fuel ratio. The cylinder head of the internal combustion engine 1 is provided with an ignition plug 7 for each cylinder, and a high voltage is applied to the ignition plug 7 of each cylinder from an ignition coil / igniter (not shown) at each ignition timing. The mixture is ignited. Then, the exhaust gas after combustion passes through the exhaust passage 8 and is discharged into the atmosphere.

An intake pressure sensor 11 is disposed in the intake passage 3 as a load sensor. The intake pressure sensor 11 detects intake pressures PM1 and PM2 on the downstream side of the throttle valve 4. An air-fuel ratio sensor 12 is provided in the exhaust passage 8, and the air-fuel ratio sensor 12 detects an air-fuel ratio (A / F) in the exhaust gas discharged from the internal combustion engine 1.

On the other hand, the fuel pump 2
The fuel pumped in 2 is pumped in the order of the fuel pipe 23, the fuel filter 24, the fuel pipe 25, and the delivery pipe 26, and is distributed and supplied to the fuel injection valve 5 of each cylinder. Excess fuel in the delivery pipe 26 is returned to the fuel tank 21 through the path of the pressure control valve (pressure regulator) 30 and the return pipe 27.

Next, the internal structure and operation of the pressure control valve 30 will be described with reference to the schematic diagram of FIG.

The pressure control valve 30 includes a back pressure chamber 31 and a fuel chamber 3.
2 are separated by a diaphragm 33. Set pressure (control pressure) of spring 34 arranged in back pressure chamber 31
As a result, the diaphragm 33 is biased, and communication between the fuel introduction pipe 35 side and the fuel discharge pipe 36 side of the fuel chamber 32 is prevented. The back pressure introduced into the back pressure introducing pipe 37 of the back pressure chamber 31 causes the pressure control valve 30 to move the diaphragm 3.
3 is displaced by a predetermined amount against the set pressure of the spring 34, and communication between the fuel introduction pipe 35 and the fuel discharge pipe 36 of the fuel chamber 32 is allowed. The fuel introduction pipe 35 is connected to the delivery pipe 2
6 and the fuel outlet pipe 36 is connected to the return pipe 27.

Further, in this embodiment, as shown in FIG. 1, the back pressure chamber 31 of the pressure control valve 30 is connected via a back pressure introducing pipe 37 to, for example, a back pressure switching valve composed of a VSV (Vacuum Switching Valve). 40. Therefore, the back pressure switching valve 40 is connected to the intake passage 3 by the intake pressure introducing pipe 41.
Side, the back pressure in the back pressure chamber 31 of the pressure control valve 30 is the intake pressure, and the back pressure switching valve 40 is
When the pressure is switched to the second side, the back pressure of the back pressure chamber 31 of the pressure control valve 30 becomes the atmospheric pressure. In this way, the fuel pressure in the delivery pipe 26 is adjusted based on the intake pressure or the atmospheric pressure, which is the back pressure from the back pressure switching valve 40, and the set pressure of the pressure control valve 30.

ECU for controlling the operating state of the internal combustion engine 1
(Electronic Control Unit) 50
Are a well-known central processing unit (CPU), a ROM storing a control program, a RAM storing various data,
/ U (backup) RAM, etc., and is configured as a logical operation circuit, and an input port and a fuel injection valve 5 for inputting detection signals from various sensors such as the above-described intake pressure sensor 11, air-fuel ratio sensor 12, etc., and back pressure switching An output port for outputting a control signal to various actuators such as the valve 40 is connected via a bus.

Next, the EC used in the atmospheric pressure detecting device of the internal combustion engine according to the first embodiment of the present invention will be described.
A description will be given based on a flowchart of FIG. 3 showing a data read processing procedure prior to the atmospheric pressure calculation in U50. This data reading routine is executed at predetermined intervals of about 32 to 512 ms, which is relatively slow in the internal combustion engine control.
It is repeatedly executed by the CU 50.

Referring to FIG. 3, first, in step S101, it is determined whether the flag XDATEND is "OFF". Here, it is determined whether the calculation of the atmospheric pressure based on the previously read data has been completed and whether the reading of the current data is permitted. In other words, this is to prevent the atmospheric pressure from being detected by confusing the read data of the previous time and the read data of the present time. The determination condition of step S101 is not satisfied,
That is, when the flag XDATEND is "ON" and the data reading necessary for calculating the atmospheric pressure has been completed, but the calculation of the atmospheric pressure has not been completed, the routine ends and the apparatus enters a standby state.

On the other hand, when the determination condition of step S101 is satisfied, that is, when the flag XDATEND is "OFF" and the calculation of the atmospheric pressure is completed, the process proceeds to step S102, and whether the operating state of the internal combustion engine 1 is stable or not. Is determined. Here, when the vehicle is in a transient state such as acceleration or deceleration, the intake pressure, the fuel injection amount, the air-fuel ratio, and the like in the operating state of the internal combustion engine 1 vary, and the error in the atmospheric pressure calculated as a result increases. It is determined whether the operating state of the internal combustion engine is sufficiently stable based on the engine load, the engine speed, and the like.

When the determination condition of step S102 is satisfied, that is, when the operation state of the internal combustion engine 1 is stable, the process proceeds to step S103, and it is determined whether the processing IDX is "0". Here, before actually reading data, the back pressure chamber 3 of the pressure control valve 30 is controlled by the back pressure switching valve 40.
1, when the intake pressure in the intake passage 3 is introduced (process IDX = 0), the back pressure switching valve 40 controls the pressure control valve 30
When the atmospheric pressure is introduced into the back pressure chamber 31 (processing ID
X = 1) is determined. Step S10
When the determination condition of 3 is satisfied, that is, when the process IDX is “0” and the intake pressure is introduced into the back pressure chamber 31 of the pressure control valve 30, the process proceeds to step S 104, and the intake pressure sensor 11
Is read from the intake pressure PM1. Next, step S10
The program proceeds to 5 where an air-fuel ratio F / B (feedback) correction coefficient FAF1, which is a value related to the air-fuel ratio at this time, is read.

Thus, the data reading process is completed when the intake pressure is introduced into the back pressure chamber 31 of the pressure control valve 30, but the atmospheric pressure is introduced into the back pressure chamber 31 of the pressure control valve 30. Preparation for the data reading process when the
It is executed from 06 to step S108. Step S1
In 06, the back pressure introduced into the back pressure chamber 31 of the pressure control valve 30 by the back pressure switching valve 40 is switched from the intake pressure to the atmospheric pressure as the back pressure switching process. Next, the process proceeds to step S107, where the processing IDX is set from “0” to “1”. Then, the process proceeds to step S108, where the back pressure switching valve 4
Counter C for preventing data reading immediately after the back pressure is switched, which is introduced into the back pressure chamber 31 of the pressure control valve 30 by 0
After resetting NTDLY to "0" and starting the reset, this routine ends.

On the other hand, the determination condition of step S103 is not satisfied, that is, the process IDX is "1" and the back pressure switching valve 40
When the atmospheric pressure is introduced into the back pressure chamber 31 of the pressure control valve 30, the process proceeds to step S109, and it is determined whether the counter CNTDLY exceeds a predetermined value (predetermined time) α. When the determination condition of step S109 is not satisfied, that is, when the counter CNTDLY is equal to or smaller than the predetermined value α, the present routine is terminated and the apparatus enters a standby state.
On the other hand, the determination condition of step S109 is satisfied, that is, the counter CNTDLY has exceeded the predetermined value α, and the back pressure switching valve 4
If a sufficient time for stabilizing the back pressure introduced into the back pressure chamber 31 of the pressure control valve 30 by 0 has elapsed, the process proceeds to step S110, and the intake pressure PM2 from the intake pressure sensor 11 is read. . Next, the process proceeds to step S111, and it is determined whether the absolute value obtained by subtracting the intake pressure PM2 read in step S110 from the intake pressure PM1 read in step S104 is less than a predetermined pressure β. The determination condition of step S111 is not satisfied, that is,
When the differential pressure between the intake pressure PM1 and the intake pressure PM2 is greater than or equal to the predetermined pressure β, it is determined that there is some change in the operating state of the internal combustion engine 1, and this routine ends.

On the other hand, when the determination condition of step S111 is satisfied, that is, when the differential pressure between the intake pressure PM1 and the intake pressure PM2 is smaller than the predetermined pressure β, it is determined that there is no change in the operating state of the internal combustion engine 1, and the process proceeds to step S112. The air-fuel ratio F / B correction coefficient FA, which is a value related to the air-fuel ratio at this time,
F2 is read. Next, proceeding to step S113,
As the back pressure switching process, the back pressure introduced into the back pressure chamber 31 of the pressure control valve 30 is switched from the atmospheric pressure to the intake pressure by the back pressure switching valve 40. Next, the process proceeds to step S114, where the processing IDX is set from “1” to “0”. And
In step S115, it is determined that data reading has been completed, the flag XDATEND is set to "ON", and the routine ends.

On the other hand, when the determination condition of step S102 is not satisfied, that is, when the operating state of the internal combustion engine 1 is not stable, the process proceeds to step S116, and the above-described step S1 is performed.
At 06, the back pressure introduced into the back pressure chamber 31 of the pressure control valve 30 by the back pressure switching valve 40 is switched from the atmospheric pressure to return to the intake pressure. Next, the process proceeds to step S117, where the processing IDX set to “1” in step S107 is canceled to “0”.

Next, a counter for preventing data reading immediately after switching of the back pressure introduced into the back pressure chamber 31 of the pressure control valve 30 by the back pressure switching valve 40 used in the data reading routine of FIG. This will be described with reference to the flowchart of FIG. 4 showing the procedure of the count-up process of CNTDLY.

In FIG. 4, in step S201, the counter CNTDLY is incremented by "1". Next, the process proceeds to step S202, and as a MAX (upper limit) guard process for preventing the counter CNTDLY from overflowing, the MIN (smaller one) of the counter CNTDLY value and the preset CNTMX value is used as the counter CNTDL.
After setting the Y value, this routine ends.

Next, the EC used in the atmospheric pressure detecting device of the internal combustion engine according to the first embodiment of the present invention will be described.
A description will be given based on the flowchart of FIG. 5 showing the processing procedure for calculating the atmospheric pressure in U50. Note that this atmospheric pressure calculation routine is repeatedly executed by the ECU 50 at intervals of about 32 to 512 ms, which are relatively slow in the internal combustion engine control as a predetermined time.

In FIG. 5, first, at step S301
It is determined whether the flag XDATEND is "ON". If the determination condition in step S301 is not satisfied, that is, if the flag XDATEND is “OFF” and the data reading required for calculating the atmospheric pressure has not been completed, this routine ends and the apparatus enters a standby state. On the other hand, when the determination condition of step S301 is satisfied, that is, when the flag XDATEND is “ON” and the data reading necessary for calculating the atmospheric pressure has been completed, the process proceeds to step S302, and the fuel injection amount increase rate K
The FUP is the air-fuel ratio F read in step S105 of FIG.
It is calculated by the following equation (1) based on the / B correction coefficient FAF1 and the air-fuel ratio F / B correction coefficient FAF2 read in step S112.

[0030]

KFUP = FAF1 / FAF2 (1) Next, the process proceeds to step S303, in which the fuel injection amount increase rate KFUP and the pressure change rate KP calculated in step S302.
From the following equation (2) showing the relationship with UP, the pressure change rate KPUP
Is derived as shown in the following equation (3).

[0031]

## EQU2 ## KFUP = (KPUP) ^1/2 (2)

[0032]

Equation 3] ^{KPUP = (KFUP) 2 ··· (} 3) then the process proceeds to step S304, the intake pressure change rate KPUP the atmospheric pressure PA calculated at step S303 pressure P
The atmospheric pressure PA is derived from the following equation (4) showing the relationship with M as shown in the following equation (5). Here, PPR is a set pressure determined by the biasing force of the spring 34 of the pressure control valve 30, and the intake pressure PM is an average of the intake pressure PM1 read in step S104 and the intake pressure PM2 read in step S110 of FIG. This is the intake pressure subjected to the smoothing process.

[0033]

## EQU00004 ## KPUP = {PPR + (PA-PM)} / PPR (4)

[0034]

## EQU00005 ## PA = PPR (KPUP-1) + PM (5) Next, the process proceeds to step S305, where the calculation of the atmospheric pressure based on the data read this time is completed, and the data reading routine of FIG. The flag XDATEND is set to "OFF" to permit the next data reading, and the routine ends.

As described above, the apparatus for detecting the atmospheric pressure of the internal combustion engine according to the present embodiment includes the fuel injection valve 5 for supplying the fuel injection amount set in accordance with the operating state to the internal combustion engine 1 and the fuel pump 22.
A pressure control valve 30 for adjusting a fuel pressure which is a pressure of the fuel applied to the fuel injection valve 5 and a suction pressure sensor 11 as a load sensor for detecting a load (intake pressure) of the internal combustion engine 1
An ECU 50 for calculating or estimating an intake pressure PM in the intake passage 3 based on an output from the intake pressure sensor 11 and an air-fuel ratio sensor 12 for detecting an air-fuel ratio of exhaust gas of the internal combustion engine 1
And a value related to the air-fuel ratio based on each output from the air-fuel ratio sensor 12 when the intake pressure PM or the atmospheric pressure PA is introduced into the back pressure chamber 31 of the pressure control valve 30. ECU 50 for calculating each air-fuel ratio related value
And an increase rate of the fuel injection amount caused by a change in the differential pressure obtained by subtracting the intake pressure PM from the fuel pressure applied to the fuel injection valve 5 based on the ratio of the air-fuel ratio-related value. An increase rate calculating means achieved by the ECU 50, which is calculated as a rate KFUP, and a fuel injection amount increase rate KF
Change rate calculation means achieved by the ECU 50 for calculating the change rate of the differential pressure applied to the fuel injection valve 5 from the UP as the differential pressure change rate KDUP, and setting of the differential pressure change rate KD, the intake pressure PM, and the pressure control valve 30 Atmospheric pressure calculating means which is achieved by the ECU 50 which calculates the atmospheric pressure PA from the pressure PPR. In addition, the air-fuel ratio related value is
The air-fuel ratio F / B (feedback) correction coefficients FAF1 and FAF2 for correcting the fuel injection amount so that the air-fuel ratio calculated based on the output from the ECU become the target air-fuel ratio.

That is, when the intake pressure PM or the atmospheric pressure PA is introduced as the back pressure of the back pressure chamber 31 of the pressure control valve 30, the fuel pressure applied to the fuel injection valve 5 includes the difference between the intake pressure PM and the atmospheric pressure PA. A differential pressure (pressure difference) based on the difference occurs. This differential pressure appears as a change in the fuel injection amount from the fuel injection valve 5, and the air-fuel ratio F / B correction coefficients FAF1 and FAF2 are calculated as air-fuel ratio-related values based on the respective outputs from the air-fuel ratio sensor 12. A fuel injection amount increase rate KFUP, which is an increase rate of the fuel injection amount from the fuel injection valve 5, is calculated based on the ratio of the air-fuel ratio F / B correction coefficients FAF1 and FAF2, and the fuel injection valve is calculated from the fuel injection amount increase rate KFUP. The differential pressure change rate KPUP, which is the rate of change of the differential pressure according to No. 5, is calculated.

In this way, since the differential pressure change rate KPUP, the intake pressure PM by the intake pressure sensor 11, and the set pressure PPR of the pressure control valve 30 are known, the above equations (1), (3), and (5) are obtained.
The atmospheric pressure PA is calculated based on Therefore, the atmospheric pressure PA can be calculated not only in the high load operation state of the conventional internal combustion engine 1 but also in the medium / low load operation state, and the error between the atmospheric pressure obtained by the atmospheric pressure detection processing and the current atmospheric pressure is obtained. Can be reduced. Thereby, the reliability of the atmospheric pressure PA by the atmospheric pressure detection processing can be improved.

<Embodiment 2> FIG. 6 is a flowchart showing a data reading processing procedure prior to the calculation of the atmospheric pressure in the ECU 50 used in the atmospheric pressure detecting device of the internal combustion engine according to the second embodiment of the present invention. It is. Note that this data reading routine is executed as a predetermined time every 32 to 512 ms, which is relatively slow in the internal combustion engine control.
It is repeatedly executed at 0.

Here, the overall structure of the atmospheric pressure detecting device for an internal combustion engine according to the present embodiment is similar to that of the first embodiment described above with reference to FIG. 1 except that the back pressure switching valve 40 connected to the pressure control valve 30 is eliminated. The only difference is that atmospheric pressure is always introduced into the back pressure chamber 31 of the control valve 30, and the other parts are the same. Further, since the pressure control valve 30 of FIG. 2 in the first embodiment described above is the same, a detailed description thereof will be omitted. Further, the description of the same processing portions as those of the data reading routine of FIG. 3 in the first embodiment will be simplified.

In FIG. 6, first, in step S401, it is determined whether the flag XDATEND is "OFF". When the determination condition of step S401 is satisfied, that is, when the flag XDATEND is “OFF” and the calculation of the atmospheric pressure is completed, the process proceeds to step S402, and it is determined whether the operating state of the internal combustion engine 1 is stable. When the determination condition of step S402 is satisfied, that is, when the operating state of the internal combustion engine 1 is stable, the process proceeds to step S403,
Atmospheric pressure change estimation counter CNTLV for limiting the time required to read data required to calculate atmospheric pressure
It is determined whether L exceeds a predetermined value (predetermined time) γ. The predetermined value γ in this determination is determined by the first data group and the second data group.
This is a time for preventing data from being read under a different atmospheric pressure with a data group, and is set in advance by adaptation. Here, the atmospheric pressure change is estimated for a predetermined time, but can be estimated based on the traveling distance.

When the determination condition of step S403 is satisfied, that is, when it is estimated that the atmospheric pressure change determination counter CNTLVL has exceeded the predetermined value γ and the predetermined time has elapsed, and there is a change in the atmospheric pressure, the process proceeds to step S404. Since the atmospheric pressure cannot be calculated using one data group, the rewriting process of the first data group is executed in steps S404 to S409. In step S404, the intake pressure PM1 from the intake pressure sensor 11 is read. Next, the routine proceeds to step S405, where the fuel injection valve differential pressure correction execution flag XREVINJ
Is "OFF". Here, it is determined whether or not the correction of the fuel injection amount from the fuel injection valve 5 is executed based on the differential pressure obtained by subtracting the intake pressure from the fuel pressure (fuel pressure). That is, data is not read when the correction of the fuel injection amount from the fuel injection valve 5 is being executed.

The condition of step S405 is satisfied, that is, the fuel injection valve differential pressure correction execution flag XREVINJ is set to "O".
FF ", and when the correction of the fuel injection amount from the fuel injection valve 5 has been stopped, the process proceeds to step S406, and the counter C for measuring the stop time of the fuel injection valve differential pressure correction.
It is determined whether NTDLY is equal to or greater than a predetermined value (predetermined time) δ. The predetermined value δ in this determination is a time until the air-fuel ratio F / B correction becomes stable (convergence), and is set in advance by adaptation. When the determination condition in step S406 is not satisfied, that is, when the counter CNTDLY is less than the predetermined value δ, the present routine is terminated and the apparatus enters a standby state.

On the other hand, the determination condition of step S406 is satisfied, that is, when the counter CNTDLY is equal to or more than the predetermined value δ,
If a sufficient time has elapsed for stabilizing the air-fuel ratio F / B correction, the process proceeds to step S407, and the air-fuel ratio F / B correction coefficient FAF which is a value related to the air-fuel ratio at this time.
1 is read. Since the air-fuel ratio F / B correction coefficient is constantly changing according to the change in the air-fuel ratio, it is averaged or smoothed. Thus, the data reading process for the first data group has been completed, but the process proceeds to step S408,
The atmospheric pressure change determination counter CNTLVL is reset to "0". Next, the routine proceeds to step S409, where the fuel injection valve differential pressure correction execution flag XREVINJ is changed from "OFF" to "O".
N ", and the routine ends after the fuel injection valve differential pressure correction is restored. On the other hand, the determination condition of step S405 is not satisfied, that is, the fuel injection valve differential pressure correction execution flag XRE
When VINJ is "ON" and the correction of the fuel injection amount from the fuel injection valve 5 is being performed by the differential pressure obtained by subtracting the intake pressure from the fuel pressure (fuel pressure), the flow shifts to step S410, where the fuel injection valve differential pressure is set. When the correction execution flag XREVINJ is
FF "and the fuel injection valve differential pressure correction is stopped. Then, the flow shifts to step S411, where the counter CNTDLY is set to "0" and the reset is started, followed by terminating the present routine.

If the condition of step S403 is not satisfied,
That is, when it is estimated that the atmospheric pressure change determination counter CNTLVL is equal to or less than the predetermined value γ and the predetermined time has not elapsed and there is no change in the atmospheric pressure, the rewriting process of the second data group is executed in steps S412 to S419. Is done. In step S412, the intake pressure PM2 from the intake pressure sensor 11 is read. Next, the process proceeds to step S413, and the process proceeds to step S4 from the intake pressure PM1 read in step S404.
It is determined whether the absolute value obtained by subtracting the intake pressure PM2 read in step S12 exceeds a predetermined pressure ε.
The predetermined pressure ε in this determination is a differential pressure necessary to increase the accuracy of atmospheric pressure detection, and is set in advance by adaptation. The determination condition of step S413 is not satisfied, that is,
When the differential pressure between the intake pressure PM1 and the intake pressure PM2 is smaller than the predetermined pressure ε, the accuracy of the atmospheric pressure detection is not good, so this routine is terminated and the apparatus enters a standby state until the differential pressure increases.

On the other hand, when the determination condition of step S413 is satisfied, that is, when the pressure difference between the intake pressure PM1 and the intake pressure PM2 is larger than the predetermined pressure ε, it is determined that the accuracy of the atmospheric pressure detection is sufficiently obtained, and the process proceeds to step S414. It is determined whether the fuel injection valve differential pressure correction execution flag XREVINJ is "OFF". The determination condition of step S414 is satisfied, that is, the fuel injection valve differential pressure correction execution flag XREVINJ is set to "O
FF ", and when the correction of the fuel injection amount from the fuel injection valve 5 has been stopped, the process proceeds to step S415, and the counter C for measuring the stop time of the fuel injection valve differential pressure correction.
It is determined whether NTDLY is equal to or greater than a predetermined value δ. The determination condition of step S415 is not satisfied, that is, the counter CN
When TDLY is less than the predetermined value δ, the present routine is terminated and the apparatus enters a standby state.

When the determination condition of step S415 is satisfied, that is, when the counter CNTDLY is equal to or more than the predetermined value δ and a sufficient time has elapsed for stabilizing the air-fuel ratio F / B correction, the process proceeds to step S416. The air-fuel ratio F / B correction coefficient FAF2, which is a value related to the current air-fuel ratio, is read. Thus, the data reading process for the second data group is completed, but the flow shifts to step S417, and the atmospheric pressure change determination counter CNTLVL is reset to "0". Next, the flow shifts to step S418, where the fuel injection valve differential pressure correction execution flag XREVINJ is changed from "OFF" to "ON".
And the fuel injection valve differential pressure correction is restored. Next, the flow shifts to step S419, where it is determined that data reading has been completed, the flag XDATEND is set to "ON", and this routine ends.

On the other hand, the condition of step S414 is not satisfied, that is, the fuel injection valve differential pressure correction execution flag XREVIN
When J is “ON” and the correction of the fuel injection amount for the fuel injection valve 5 is being executed, the process proceeds to step S410, and the fuel injection valve differential pressure correction execution flag XREVINJ is set to “O”.
FF "and the fuel injection valve differential pressure correction is stopped. Then, the flow shifts to step S411, where the counter CNTDLY is set to "0" and the reset is started, followed by terminating the present routine.

On the other hand, when the determination condition of step S401 is not satisfied, that is, when the flag XDATEND is "ON" and the data reading necessary for calculating the atmospheric pressure has been completed, but the calculation of the atmospheric pressure has not been completed yet. Or step S40
When the determination condition of 2 is not satisfied, that is, when the operating state of the internal combustion engine 1 is not stable, the process proceeds to step S420,
Fuel injection valve differential pressure correction execution flag XREVINJ is "ON"
After that, the present routine is terminated and a standby state is set.

Next, the count-up process of the counter CNTDLY for measuring the stop time of the fuel injection valve differential pressure correction used in the data read routine of FIG. 6 and the counter CNTLVL for limiting the elapsed time of the data read. Will be described based on the flowchart of FIG.

In FIG. 7, in step S501, the counter CNTDLY is incremented by "1". Next, in step S502, as a MAX (upper limit) guard process for preventing the counter CNTDLY from overflowing, the MIN (smaller one) of the counter CNTDLY value and the preset CNTMX1 value is set to the counter CNT.
DLY value. Next, the flow shifts to step S503, where the counter CNTLVL is incremented by "1". Next, the process proceeds to step S504, and as a MAX (upper limit) guard process for preventing the counter CNTLVL from overflowing, the MIN (smaller one) of the counter CNTLVL value at that time and the preset CNTMX2 value is used as the counter CNT.
After the LVL value is set, this routine ends.

Next, the EC used in the atmospheric pressure detecting device for the internal combustion engine according to the second embodiment of the present invention will be described.
The process of calculating the atmospheric pressure in U50 will be described with reference to the flowchart of FIG. Note that this atmospheric pressure calculation routine is repeatedly executed by the ECU 50 at intervals of about 32 to 512 ms, which are relatively slow in the internal combustion engine control as a predetermined time. Further, the description of the same processing part as the atmospheric pressure calculation routine of FIG. 5 in the first embodiment will be simplified.

In FIG. 8, first, in step S601,
It is determined whether the flag XDATEND is "ON". If the determination condition in step S601 is not satisfied, that is, if the flag XDATEND is “OFF” and the data reading required for calculating the atmospheric pressure has not been completed, this routine ends and the apparatus enters a standby state. On the other hand, when the determination condition of step S601 is satisfied, that is, when the flag XDATEND is “ON” and the data reading necessary for calculating the atmospheric pressure has been completed, the process proceeds to step S602, and the fuel injection amount increase rate K
The FUP is the air-fuel ratio F read in step S407 of FIG.
It is calculated by the following equation (6) based on the / B correction coefficient FAF1 and the air-fuel ratio F / B correction coefficient FAF2 read in step S416.

[0053]

KFUP = FAF1 / FAF2 (6) Next, the process proceeds to step S603, where the pressure change rate K is calculated from the fuel injection amount increase rate KFUP calculated in step S602.
PUP is calculated by the following equation (7).

[0054]

KUP = (KFUP) ² (7) Next, the process proceeds to step S604, in which the pressure change rate KUPP and the atmospheric pressure PA calculated in step S603 and the suction pressure read in step S404 in FIG. The atmospheric pressure PA is derived as shown in the following equation (9) from the following equation (8) showing the relationship between the air pressure PM1 and the intake pressure PM2 read in step S412.

[0055]

[Expression 8] KPUP = {PPR + (PA−PM2)} / {PPR + (PA−PM1)} (8)

[0056]

PA = {PPR (KPUP−1) −KUPP · PM1 + PM2} / (1−KUPP) (9) Next, the process proceeds to step S605 to calculate the atmospheric pressure based on the data read this time. This is the end, the flag XDATEND is set to "OFF" to permit the next data reading in the data reading routine of FIG. 6, and the routine ends.

As described above, the apparatus for detecting the atmospheric pressure of the internal combustion engine according to the present embodiment includes the fuel injection valve 5 for supplying the fuel injection amount set according to the operating state to the internal combustion engine 1 and the fuel pump 22.
A pressure control valve 30 for adjusting a fuel pressure which is a pressure of the fuel applied to the fuel injection valve 5 and a suction pressure sensor 11 as a load sensor for detecting a load (intake pressure) of the internal combustion engine 1
An air-fuel ratio sensor 12 for detecting an air-fuel ratio of exhaust gas of the internal combustion engine 1;
Pressure calculation means, which is achieved by the ECU 50 for calculating or estimating the respective intake pressures PM1 and PM2 in the intake passage 3 in the first operating state or the second operating state, and the magnitude of the differential pressure applied to the fuel injection valve 5. Pressure correction means achieved by the ECU 50 that corrects the fuel injection amount by means of the pressure control unit 30 and the atmospheric pressure PA introduced into the back pressure chamber 31 of the pressure control valve 30 so that the air-fuel ratio in the first operating state or the second operating state is increased. Sensor 12
Related value calculating means, which is achieved by the ECU 50 for calculating a value related to the air-fuel ratio based on each output from the ECU as an air-fuel ratio related value, and a fuel pressure applied to the fuel injection valve 5 based on the ratio of the air-fuel ratio related values. An increase rate calculating means which is achieved by the ECU 50 which calculates an increase rate of the fuel injection amount caused by a change in the differential pressure obtained by subtracting the intake pressures PM1 and PM2 as a fuel injection amount increase rate KFUP, and a fuel injection amount increase rate KFUP
From the ECU 50, which calculates the rate of change of the differential pressure applied to the fuel injection valve 5 as the differential pressure change rate KD, and the differential pressure change rate KD and the intake pressures PM1, P
An atmospheric pressure calculating means which is achieved by the ECU 50 for calculating the atmospheric pressure PA from M2 and the set pressure PPR of the pressure control valve 30 is provided. Further, the air-fuel ratio related values are air-fuel ratio F / B (feedback) correction coefficients FAF1 and FAF2 for correcting the fuel injection amount so that the air-fuel ratio calculated based on the output from the air-fuel ratio sensor 12 becomes the target air-fuel ratio. It is. When the differential pressure correcting means achieved by the ECU 50 detects the intake pressures PM1 and PM2 and the air-fuel ratio F / B (feedback) correction coefficients FAF1 and FAF2 in the first operating state or the second operating state, the fuel pressure increases. The correction of the fuel injection amount from the injection valve 5 is stopped.

That is, the atmospheric pressure PA is introduced as the back pressure of the back pressure chamber 31 of the pressure control valve 30, and the intake pressure PM 1 in the first operation state by the intake pressure sensor 11 differs from the second operation state in which the intake pressure is different. An intake pressure PM2 is calculated.
The difference between the pressure difference before and after the fuel injection valve 5 in the first operation state and the second operation state in which the intake pressures are different appears as a change in the fuel injection amount, and based on the output from the air-fuel ratio sensor 12, the air-fuel ratio F / It is calculated as B correction coefficients FAF1 and FAF2. Here, the fuel injection amount is corrected by the magnitude of the differential pressure applied to the fuel injection valve 5, and the intake pressures PM1 and PM2 and the air-fuel ratio F / B correction coefficient FAF1 in the first operation state or the second operation state. , FAF2, the correction of the fuel injection amount is stopped, so that these detected values can be stably obtained without being affected by the correction. A fuel injection amount increase rate KFUP, which is an increase rate of the fuel injection amount from the fuel injection valve 5, is calculated based on the ratio of the air-fuel ratio F / B correction coefficients FAF1 and FAF2, and the fuel injection valve is calculated from the fuel injection amount increase rate KFUP. The differential pressure change rate KPUP, which is the rate of change of the differential pressure according to No. 5, is calculated.

In this manner, the differential pressure change rate KPUP, the intake pressures PM1 and PM2, and the set pressure PPR of the pressure control valve 30 are known, so that the atmospheric pressure PA can be obtained based on the above equations (6), (7) and (9). Is calculated. Therefore, the atmospheric pressure PA can be calculated not only in the high load operation state of the conventional internal combustion engine 1 but also in the medium / low load operation state, and the error between the atmospheric pressure obtained by the atmospheric pressure detection processing and the current atmospheric pressure is obtained. Can be reduced. Thereby, the atmospheric pressure PA by the atmospheric pressure detection processing is obtained.
Reliability can be improved.

In the above embodiment, the intake pressure is directly detected by using the intake pressure sensor 11 as a load sensor. However, the present invention is not limited to this. The present invention can also be applied to a system for detecting the amount of air introduced into an internal combustion engine by an air flow meter or the like.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an overall configuration of an atmospheric pressure detecting device for an internal combustion engine according to a first example of an embodiment of the present invention.

FIG. 2 is a schematic diagram showing an internal configuration of a pressure control valve used in FIG.

FIG. 3 is an ECU used in an atmospheric pressure detecting device for an internal combustion engine according to a first embodiment of the present invention;
6 is a flowchart showing a data read processing procedure in FIG.

FIG. 4 is a flowchart showing a procedure of a count-up process of a counter of FIG. 3;

FIG. 5 is an ECU used in an atmospheric pressure detection device for an internal combustion engine according to a first example of an embodiment of the present invention.
It is a flowchart which shows the processing procedure of atmospheric pressure calculation in FIG.

FIG. 6 is an ECU used in an atmospheric pressure detection device for an internal combustion engine according to a second embodiment of the present invention.
6 is a flowchart showing a data read processing procedure in FIG.

FIG. 7 is a flowchart illustrating a count-up processing procedure of the counter in FIG. 6;

FIG. 8 is an ECU used in an atmospheric pressure detecting device for an internal combustion engine according to a second embodiment of the present invention.
It is a flowchart which shows the processing procedure of atmospheric pressure calculation in FIG.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 internal combustion engine 5 fuel injection valve 11 intake pressure sensor (load sensor) 12 air-fuel ratio sensor 22 fuel pump 30 pressure control valve 31 back pressure chamber 50 ECU (electronic control unit)

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3G084 BA09 BA13 BA14 CA03 CA04 DA04 DA07 DA13 EA05 EB12 EB25 EC04 FA01 FA11 FA18 FA29 3G301 JA08 KA08 LB06 MA01 MA11 NA01 NA08 NB11 ND01 NE01 NE17 NE23 PA07Z PA09Z PA17Z PEBZZ PD03

Claims (4)

[Claims] 1. A fuel injection valve for supplying a fuel injection amount set according to an operation state to an internal combustion engine, and a pressure control for adjusting a fuel pressure which is pressurized by a fuel pump and is a pressure of fuel applied to the fuel injection valve. A valve, a load sensor for detecting a load of the internal combustion engine, an air-fuel ratio sensor for detecting an air-fuel ratio of exhaust gas of the internal combustion engine, and calculating or estimating an intake pressure in an intake passage based on an output from the load sensor. An air pressure ratio calculating means, and a value related to the air fuel ratio based on each output from the air fuel ratio sensor when the air pressure or the atmospheric pressure is introduced into the back pressure chamber of the pressure control valve. Related value calculating means for calculating a value of the air-fuel ratio related value, and an increase rate of the fuel injection amount caused by a change in a differential pressure obtained by subtracting the intake pressure from the fuel pressure applied to the fuel injection valve based on a ratio of the air-fuel ratio related value. An increase rate calculating means for calculating a fuel injection amount increase rate; a change rate calculating means for calculating a change rate of a differential pressure applied to the fuel injection valve from the fuel injection amount increase rate as a differential pressure change rate; An atmospheric pressure detecting device for an internal combustion engine, comprising: atmospheric pressure calculating means for calculating the atmospheric pressure from a rate, the intake pressure, and a set pressure of the pressure control valve. 2. A fuel injection valve for supplying a fuel injection amount set according to an operation state to an internal combustion engine, and a pressure control for adjusting a fuel pressure which is pressurized by a fuel pump and is a pressure of the fuel applied to the fuel injection valve. A valve, a load sensor that detects a load of the internal combustion engine, an air-fuel ratio sensor that detects an air-fuel ratio of exhaust gas of the internal combustion engine, and a first operation state or a second operation based on an output from the load sensor. Intake pressure calculating means for calculating or estimating each intake pressure in the intake passage in the state; differential pressure correcting means for correcting the fuel injection amount according to the magnitude of the differential pressure applied to the fuel injection valve; and the pressure control valve Atmospheric pressure is introduced into the back pressure chamber, and a value related to the air-fuel ratio based on each output from the air-fuel ratio sensor in the first operating state or the second operating state is defined as an air-fuel ratio related value. A fuel injection amount calculated by subtracting the intake pressure from the fuel pressure applied to the fuel injection valve based on the ratio of the air-fuel ratio-related value. Rate-of-incidence calculating means for calculating the rate of change of the fuel injection amount; rate-of-change calculating means for calculating the rate of change of the differential pressure applied to the fuel injection valve from the rate of increase of the fuel injection amount as the rate of change of the differential pressure; An atmospheric pressure detecting device for an internal combustion engine, comprising: atmospheric pressure calculating means for calculating the atmospheric pressure from the intake pressure and a set pressure of the pressure control valve. 3. The air-fuel ratio-related value is a fuel injection amount such that an air-fuel ratio calculated based on an output from the air-fuel ratio sensor or an air-fuel ratio calculated based on an output from the air-fuel ratio sensor becomes a target air-fuel ratio. 3. An air-fuel ratio feedback correction coefficient for correcting the air-fuel ratio.
The atmospheric pressure detecting device for an internal combustion engine according to claim 1. 4. The fuel injection amount from the fuel injection valve during the detection period of the intake pressure and the air-fuel ratio related value in the first operating state or the second operating state. The atmospheric pressure detecting device for an internal combustion engine according to claim 2, wherein the correction of the pressure is stopped.