JPH08240146A - Atmospheric pressure detecting device - Google Patents

Abstract

PURPOSE: To accurately detect an atmospheric pressure from a suction pressure during operation by furnishing a means to correct the suction pressure sensed by a suction pressure detecting means under the specified conditions in accordance with the difference calculated by a difference calculating means, and providing a means to calculate the atmospheric pressure on the basis of the reference characteristics from the corrected suction pressure. CONSTITUTION: A suction pressure sensor 8 is furnished to detect the suction pressure located downstream of a throttle valve 5 which is installed in the suction passage 2 of an internal combustion engine 1. The relation of the suction pressure under the conditions that the throttle valve 5 is in the specified degree of throttle opening and the engine speed is the specified value to the atmospheric pressure is stored in memory previously at the reference characteristics, and when the specified conditions are met, an ECU 7 calculates the suction pressure correction value as the difference of the suction pressure detected in the specified conditions from the suction pressure in the reference characteristics. From the suction pressure for detecting the atmospheric pressure corrected with this suction pressure correction value, the atmospheric pressure is calculated by the ECU 7 on the basis of the reference characteristics. Thereby a dispersion in products of internal combustion engines 1 from article to article is corrected appropriately, and it is practicable to know the atmospheric pressure accurately 1.

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 atmospheric pressure from intake pressure during operation of an internal combustion engine.

[0002]

2. Description of the Related Art Conventionally, as a prior art document related to an atmospheric pressure detecting device, one disclosed in Japanese Patent Laid-Open No. 1-116265 is known. This document discloses a technique for obtaining the atmospheric pressure from the amount of change in the intake pressure at a predetermined throttle valve (intake throttle valve) opening.

[0003]

By the way, the amount of change in intake pressure due to variations in products among internal combustion engines may be larger than the amount of change in atmospheric pressure. As a result, the accuracy of atmospheric pressure detection can be improved. Since it becomes low, the atmospheric pressure detection device has not been put to practical use.

Therefore, the present invention has been made to solve such a problem, and atmospheric pressure detection capable of accurately knowing the atmospheric pressure from the intake pressure during operation by correcting the product variation for each internal combustion engine. The challenge is to provide equipment.

[0005]

According to a first aspect of the present invention, there is provided an atmospheric pressure detecting device for detecting an intake pressure downstream of a throttle valve disposed in an intake passage of an internal combustion engine, and the internal pressure engine. And a reference characteristic storing means for storing the relationship between the intake pressure and the atmospheric pressure in advance as a reference characteristic when the throttle valve has a predetermined throttle opening and the engine speed is a predetermined speed, and the internal combustion engine is started. Calculate a difference between the intake pressure detected by the intake pressure detection means under the predetermined condition that the predetermined atmospheric pressure is reached within a predetermined time after and the intake pressure corresponding to the predetermined atmospheric pressure in the reference characteristic. Difference calculating means, an intake pressure correcting means for correcting the intake pressure detected by the intake pressure detecting means under the predetermined condition according to the difference calculated by the difference calculating means, and the intake pressure compensating means. Those having a atmospheric pressure calculating means for calculating the atmospheric pressure on the basis of the corrected the intake pressure by means to the reference characteristic.

According to a second aspect of the present invention, the atmospheric pressure detecting device sets the predetermined throttle opening and the predetermined rotational speed under the predetermined conditions of the first aspect to the low rotation side when the throttle is fully closed.

In the atmospheric pressure detecting device according to a third aspect, the difference in the difference calculating means according to the first or second aspect is a value obtained by averaging a predetermined number of times.

[0008]

In the atmospheric pressure detecting device according to the first aspect, the difference calculating means has the throttle valve with a predetermined throttle opening and the engine speed being a predetermined speed within a predetermined time after the internal combustion engine is started. When the predetermined condition is the atmospheric pressure, the intake pressure detected by the intake pressure detecting means and the relationship between the intake pressure and the atmospheric pressure under the predetermined condition correspond to the predetermined atmospheric pressure in the reference characteristic stored in advance. The difference from the atmospheric pressure is calculated. The intake pressure correction means corrects the intake pressure detected under the predetermined condition according to the difference. From the corrected intake pressure, the atmospheric pressure calculating means calculates the atmospheric pressure based on the reference characteristic.

According to the atmospheric pressure detecting device of claim 2, claim 1
The predetermined throttle opening and the predetermined number of rotations under the predetermined conditions are set to the low rotation side when the throttle is fully closed.

According to the atmospheric pressure detecting device of claim 3,
Alternatively, the difference in the difference calculating means of claim 2 is a value obtained by averaging a predetermined number of times.

[0011]

EXAMPLES The present invention will be described below based on specific examples.

FIG. 1 is a schematic configuration diagram showing an atmospheric pressure detecting device according to an embodiment of the present invention.

In FIG. 1, 1 is an internal combustion engine, 2 is an intake passage of the internal combustion engine 1, 3 is a combustion chamber, 4 is an exhaust passage, 5 is a throttle valve, 6 is a fuel injection valve, 7 is an ECU (Electronic C).
ontrol Unit: electronic control unit). The ECU 7 contains a microcomputer including a CPU (not shown), a ROM for storing control programs and various tables, and a RAM for storing various data.

The fuel injection valve 6 attached to the intake passage 2 corresponding to the combustion chamber 3 of the internal combustion engine 1 is drive-controlled by a signal from the ECU 7. The ECU 7 includes an intake pressure sensor 8 that detects the intake pressure of the intake passage 2, a throttle sensor 9 that detects the throttle opening of the throttle valve 5, and an internal combustion engine 1.
A rotation angle sensor 10 for detecting a crank angle of a crankshaft (not shown) is connected, and an ignition coil 11 for inputting an ignition signal for setting an injection timing is connected. Further, the ECU 7 is connected with other sensors 12 such as a water temperature sensor for detecting the cooling water temperature of the internal combustion engine 1 and an oxygen sensor for detecting the oxygen (O ₂ ) concentration in the exhaust gas.

These various sensors (intake pressure sensor 8, throttle sensor 9, rotation angle sensor 10, other sensors 1
The fuel injection valve 6 is drive-controlled by the ECU 7 based on the signal input from 2), and the fuel is injected and supplied to the internal combustion engine 1. For example, the intake pressure P detected by the intake pressure sensor 8
The fuel injection time TAU is set with M as the main fuel injection amount setting factor and each detection signal of the throttle sensor 9 and the other sensor 12 as the correction fuel injection amount setting factor, and based on the ignition signal from the ignition coil 11. The fuel injection valve 6 is drive-controlled at the fuel injection time TAU in order to inject fuel at the set injection timing.

Next, the outline of the atmospheric pressure detection when the atmospheric pressure detection apparatus according to the embodiment of the present invention is applied is shown in FIG.
The table will be described.

With the throttle fully closed, for example, the engine speed is 80
The relationship between the atmospheric pressure and the intake pressure at 0 rpm has a reference characteristic in the adjustment value at the center of the valve clearance of the intake valve of the internal combustion engine. That is, normally, the intake pressure changes by about 80 mmHg between the atmospheric pressure of 760 mmHg and 540 mmHg which can be in Japan. On the other hand, the intake pressure when considering the upper and lower limits of the valve clearance is about 6
There is a change of 0 mmHg. The upper and lower limit lines of the valve clearance are substantially parallel to the reference characteristic line at the center of the valve clearance. Including other product variation factors (such as throttle leakage air amount when the throttle is fully closed) for each internal combustion engine may cause variation in intake pressure variation that exceeds the influence of atmospheric pressure.

Therefore, at the time of starting, the internal combustion engine supplies an intake pressure below a predetermined rotation speed to the atmospheric pressure PAS at the time of starting (760 mm in FIG. 2).
Hg), and the intake air pressure PMS at the time of fully closing the throttle corresponding to the atmospheric pressure PAS at the time of starting (a value on the valve clearance upper limit line in FIG. 2 for convenience) is taken immediately after the starting. In addition, E corresponding to the atmospheric pressure PAS at the time of starting
The throttle fully closed intake pressure PMSO in the reference characteristic stored in advance in the ROM of the CU 7 is obtained. And
The difference between the obtained throttle fully closed intake air pressure PMSO and the throttle fully closed intake air pressure PMS that has been taken in is stored in the RAM in the ECU 7 as the intake pressure correction value ΔPM for this internal combustion engine.

In the subsequent running, the intake pressure PM is taken in at the timing when the engine speed is within the predetermined speed when the throttle is fully closed, and the intake pressure correction value ΔPM is added to the intake pressure PM to obtain the atmospheric pressure. The detection intake pressure PMA is obtained.
Then, the atmospheric pressure PA corresponding to the intake pressure PMA for atmospheric pressure detection is obtained. As a result, it becomes possible to take in the atmospheric pressure PA in which the product variation for each internal combustion engine is corrected.

When the above-mentioned product variation for each internal combustion engine is not corrected, as shown in FIG.
The atmospheric pressure detection intake pressure corresponding to the intake pressure PM becomes PMA ', and the atmospheric pressure corresponding thereto becomes PA'. That is, this atmospheric pressure PA 'is an atmospheric pressure that is lower by about 80 mmHg than the atmospheric pressure PA detected by applying the above-described atmospheric pressure detecting device to the internal combustion engine, and the fuel injection amount correction using the atmospheric pressure, A large error occurs in control such as EGR (Exhaust Gas Recirculation) correction.

Next, the processing procedure of the CPU in the ECU 7 used in the atmospheric pressure detecting apparatus according to the embodiment of the present invention will be described in detail with reference to the flowcharts of FIGS. 3 and 4.

FIG. 3 shows an atmospheric pressure calculation routine, which will be described with reference to the tables shown in FIGS.

First, in step S101, it is determined whether the engine speed Ne of the internal combustion engine 1 is less than 100 rpm which is a predetermined speed. If the determination condition of step S101 is satisfied and the engine speed Ne is less than 100 rpm,
The routine proceeds to step S102, where the internal combustion engine 1 is close to the stopped state, and therefore the intake pressure ≈ atmospheric pressure, and the intake pressure PM at that time is stored as the starting atmospheric pressure PAS. here,
When the determination condition of step S101 is not satisfied, step S102 is skipped.

Next, in step S103, the internal combustion engine is operated within 3 minutes after starting, that is, after taking in the atmospheric pressure PAS at the time of starting, operating under the atmospheric pressure condition close to the atmospheric pressure PAS at the time of starting. It is determined whether or not it is in the state. When the determination condition of step S103 is satisfied,
In step S104, it is determined whether the throttle valve 5 is fully closed. When the determination condition of step S104 is satisfied, the routine proceeds to step S105, where the engine speed Ne is 700 r as a predetermined speed near idle.
It is determined whether it is in the range of pm to 900 rpm. When the determination condition of step S105 is satisfied and the atmospheric pressure detection condition is satisfied, the process proceeds to step S106, and the intake pressure PM at that time is stored as the throttle fully closed intake pressure PMS.

Next, in step S107, the throttle fully closed intake pressure PMSO in the reference characteristic is calculated in the table of FIG. 2 from the starting atmospheric pressure PAS and the engine speed Ne stored in step S102. Next, the routine proceeds to step S108, where the throttle fully closed intake pressure PMS stored in step S106 is subtracted from the throttle fully closed intake pressure PMSO calculated in step S107 to calculate the intake pressure correction value ΔPM, Step S109
Then, the intake pressure correction value ΔPM calculated in step S108 is stored. Here, when the determination conditions of step S103, step S104, or step S105 are not satisfied, steps S106 to S109.
The processes up to are skipped.

Next, step S110 and step S1
In step 11, similarly to step S104 and step S105, it is determined whether the throttle valve 5 is fully closed and the atmospheric pressure detection condition that the engine speed Ne is within the predetermined speed range is satisfied. Here, when the determination condition of step S110 or step S111 is not satisfied, this routine is ended. On the other hand, when the determination condition of step S111 is satisfied, the process proceeds to step S112, and the intake pressure PM at that time is read. Next in step S11
3, the atmospheric pressure detection intake pressure PMA is changed to step S
The intake pressure correction value ΔPM stored in step S109 is added to the intake pressure PM read in 112 to be calculated. Next, the routine proceeds to step S114, where the atmospheric pressure PA is calculated from the atmospheric pressure detecting intake pressure PMA calculated at step S113 and the engine speed Ne based on the table of FIG. 5, and this routine ends. The intermediate value at the engine speed Ne is obtained by interpolation calculation.

FIG. 4 is a flow chart showing the fuel injection time calculation of the atmospheric pressure detecting apparatus according to one embodiment of the present invention, which will be described with reference to the tables of FIGS. 6 and 7.

After input signals from various sensors are read in step S201, the engine speed Ne is calculated in step S202, and the intake pressure PM is calculated in step S203. Next, in step S204, the basic injection time TP is calculated based on the engine speed Ne in step S202 and the intake pressure PM in step S203. Next, the process proceeds to step S205, and the atmospheric pressure correction coefficient KPA for the atmospheric pressure PA calculated in step S114 of FIG. 3 is calculated from the table of FIG. Next, in step S206, the intake pressure correction coefficient KPM for the intake pressure PM calculated in step S203 is calculated from the table in FIG. Next, the process proceeds to step S207, and the final injection time TAU is calculated by the following equation.

[0029]

[Formula 1] TAU = TP * (1 + KPA * KPM) Next, the process proceeds to step S208, and the fuel injection valve 6 is operated based on the final injection time TAU calculated in step S207.
Is controlled, and this routine ends.

As described above, the atmospheric pressure detecting apparatus according to the present embodiment is provided with the intake pressure sensor 8 for detecting the intake pressure PM downstream of the throttle valve 5 arranged in the intake passage 2 of the internal combustion engine 1. In the detecting means and the ECU 7 which stores the relationship between the intake pressure and the atmospheric pressure in advance as a reference characteristic when the throttle valve 5 of the internal combustion engine 1 has a predetermined throttle opening and the engine speed Ne is a predetermined speed. The achieved reference characteristic storage means, the intake pressure PMS detected by the intake pressure detection means under the predetermined condition that a predetermined atmospheric pressure is obtained within 3 minutes after the start of the internal combustion engine 1, and the predetermined reference characteristic. Difference calculation means achieved by the ECU 7 for calculating the intake pressure correction value ΔPM as a difference from the intake pressure PMSO corresponding to the atmospheric pressure of the intake pressure PMSO, and the intake pressure detected by the intake pressure detection means under the predetermined condition. The ECU 7 that corrects the atmospheric pressure PM according to the intake pressure correction value ΔPM calculated by the difference calculation means.
And the atmospheric pressure calculation means achieved by the ECU 7 that calculates the atmospheric pressure PA based on the reference characteristic from the atmospheric pressure detection intake pressure PMA corrected by the intake pressure correction means. And is provided, which can be an embodiment of claim 1.

Therefore, when the internal combustion engine 1 is started within 3 minutes by the difference calculating means achieved by the ECU 7, the throttle valve 5 has a predetermined throttle opening and the engine speed is a predetermined condition. , The intake pressure PMS in the reference characteristic in which the relationship between the intake pressure PM detected by the intake pressure sensor 8 and the intake pressure and the atmospheric pressure under a predetermined condition is stored in advance.
The difference ΔPM from O is calculated. The intake pressure correction means achieved by the ECU 7 corrects the intake pressure PM detected under the predetermined condition according to the difference ΔPM. From the corrected intake pressure PMA, the atmospheric pressure PA is calculated by the atmospheric pressure calculating means achieved by the ECU 7 based on the reference characteristic.

Therefore, the product variation for each internal combustion engine is corrected, and the atmospheric pressure can be accurately known from the intake pressure during operation. As a result, it is possible to improve the accuracy in various controls of the internal combustion engine in which the atmospheric pressure is the control factor.

Further, the predetermined throttle opening and the predetermined rotation speed under the predetermined conditions of the atmospheric pressure detecting apparatus of the present embodiment are such that the engine rotation speed Ne is 700 rp when the throttle is fully closed.
The low rotation side is from m to 900 rpm, which can be the embodiment of claim 2.

Therefore, the predetermined throttle opening and the predetermined rotation speed under the predetermined conditions are set to the low rotation side when the throttle is fully closed. Therefore, the intake pressure taken into the internal combustion engine under the predetermined condition can be regarded as the atmospheric pressure, and the highly reliable intake pressure correction value ΔPM can be obtained.

By the way, in the above embodiment, the intake pressure correction value ΔPM as a difference within 3 minutes after the start of the internal combustion engine.
However, the intake pressure correction value ΔPM with high reliability is obtained by averaging the obtained values for a predetermined number of times instead of updating the values within 3 minutes after the start every time the routine processing is performed. Can be obtained. Further, when the present invention is carried out, the present invention is not limited to this, and the intake pressure correction value ΔPM may be stored at each start and the latest predetermined number of times may be averaged.

The difference ΔPM in the difference calculating means achieved by the ECU 7 of such an atmospheric pressure detecting device is a value obtained by averaging a predetermined number of times.
Can be used as an example.

[0037]

As described above, according to the atmospheric pressure detecting device of the first aspect, the difference calculating means allows the throttle valve to have a predetermined throttle opening and the engine speed when the internal combustion engine is within a predetermined time after starting. Is a predetermined rotation speed and a predetermined atmospheric pressure, the intake pressure detected by the intake pressure detection means and the reference characteristic in which the relationship between the intake pressure and the atmospheric pressure under the predetermined condition is stored in advance. The difference between the intake pressure and the intake pressure corresponding to the predetermined atmospheric pressure is calculated, and the intake pressure correction means corrects the intake pressure detected under the predetermined condition according to the difference. The atmospheric pressure is calculated by the calculation means based on the reference characteristic. Therefore, the product variation for each internal combustion engine is appropriately corrected, and the atmospheric pressure at that time can be accurately known from the intake pressure during operation. As a result, it is possible to improve the accuracy in various controls of the internal combustion engine in which the atmospheric pressure is the control factor.

According to the atmospheric pressure detecting device of the second aspect, in addition to the effect of the first aspect, the predetermined throttle opening degree and the predetermined rotation speed under the predetermined condition are set to the low rotation side when the throttle is fully closed. As a result, the intake pressure taken into the internal combustion engine under the predetermined condition can be regarded as the atmospheric pressure, and the difference in the intake pressure correction for detecting the atmospheric pressure can be made highly reliable.

According to the atmospheric pressure detecting device of claim 3, in addition to the effect of claim 1 or claim 2, the difference in the difference calculating means is a value obtained by averaging a predetermined number of times. As a result, the difference in the intake pressure correction for detecting the atmospheric pressure can be made more reliable.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an atmospheric pressure detection device according to an embodiment of the present invention.

FIG. 2 is a table for explaining an outline of an atmospheric pressure detecting procedure when the atmospheric pressure detecting device according to the embodiment of the present invention is applied.

FIG. 3 is a flowchart showing an atmospheric pressure calculation processing procedure of a CPU in an ECU used in an atmospheric pressure detection device according to an embodiment of the present invention.

FIG. 4 is a flowchart showing a fuel injection time calculation processing procedure of a CPU in an ECU used in an atmospheric pressure detection device according to an embodiment of the present invention.

FIG. 5 is an atmospheric pressure detecting intake pressure PMA and an atmospheric pressure P used in an atmospheric pressure detecting apparatus according to an embodiment of the present invention.
6 is a table showing the relationship with A using the engine speed Ne as a parameter.

FIG. 6 is a table showing a relationship between the atmospheric pressure PA and the atmospheric pressure correction coefficient KPA used in the atmospheric pressure detecting device according to the embodiment of the present invention.

FIG. 7 is a table showing a relationship between an intake pressure PM and an intake pressure correction coefficient KPM used in the atmospheric pressure detecting device according to the embodiment of the present invention.

[Explanation of symbols]

 1 Internal Combustion Engine 2 Intake Passage 5 Throttle Valve 7 ECU (Electronic Control Unit) 8 Intake Pressure Sensor (Intake Pressure Detection Means) 9 Throttle Sensor 10 Rotation Angle Sensor

Claims (3)

[Claims] 1. An intake pressure detecting means for detecting an intake pressure downstream of a throttle valve arranged in an intake passage of an internal combustion engine, and the throttle valve of the internal combustion engine having a predetermined throttle opening and a predetermined engine speed. Reference characteristic storage means for storing a relationship between intake pressure and atmospheric pressure as a reference characteristic in a predetermined condition of rotation speed, and the predetermined condition that the predetermined atmospheric pressure is reached within a predetermined time after the internal combustion engine is started. Difference calculation means for calculating a difference between the intake pressure detected by the intake pressure detection means and the intake pressure corresponding to the predetermined atmospheric pressure in the reference characteristic, and the intake pressure when the predetermined condition is satisfied. Intake pressure correction means for correcting the intake pressure detected by the detection means according to the difference calculated by the difference calculation means; and the intake pressure corrected by the intake pressure correction means to the reference characteristic. Atmospheric pressure detecting apparatus characterized by comprising the atmospheric pressure calculating means for calculating the atmospheric pressure Zui. 2. The atmospheric pressure detection device according to claim 1, wherein the predetermined throttle opening degree and the predetermined rotation speed under the predetermined condition are set to a low rotation side when the throttle is fully closed. 3. The difference in the difference calculating means is
The atmospheric pressure detection device according to claim 1 or 2, wherein a predetermined number of times is an averaged value.