JPH06108924A - Full close standard position signal correction device for control valve of internal combustion engine - Google Patents

Abstract

PURPOSE:To provide an accurate full close standard position signal concerning a correction device for correcting the full close standard position signal taken out from the opening detection device of an exhaust reflux valve. CONSTITUTION:When a driving distance is more than a specified value, the full open position detection voltage B is taken in (step 109-111), it the exhaust gas reflux valve comes in an operational condition under its full open state and a difference Ci between values A, B which show stroke quantities are calculated in the case of a new car. (step 112). The Ci corresponds to the full close standard position signal, and is compared with the previous value C1-1 in their amplitudes (step 114), and is subjected to renewal process in response to the result of comparison (step 115, 116).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fully closed reference position signal correction device for an internal combustion engine control valve, and more particularly to a correction device for correcting a fully closed reference position signal extracted from an exhaust gas recirculation valve opening detection device. .

[0002]

2. Description of the Related Art Conventionally, a part of exhaust gas of an internal combustion engine is recirculated through an exhaust gas recirculation valve into an intake air-fuel mixture, and heat generated by combustion in an engine cylinder is absorbed by an inert gas in the exhaust gas to achieve maximum combustion. Exhaust gas recirculation (EGR: which reduces nitrogen oxides (NO _x ) in exhaust gas by lowering the temperature
Exhaust gas recirculation) devices are known. In this EGR device, when EGR is executed, the output decreases and combustion becomes unstable. Therefore, the exhaust gas recirculation amount (EGR amount) is appropriately controlled by controlling the opening degree of the exhaust gas recirculation valve according to the operating state. is doing.

However, when the exhaust recirculation valve changes in the fully closed reference position due to thermal expansion, aging, etc., the output opening detection value of the exhaust recirculation valve opening detection device and the actual opening of the exhaust recirculation valve are detected. Therefore, an appropriate EGR amount feedback control cannot be performed.

Therefore, conventionally, when the state in which the opening command value of the exhaust gas recirculation valve indicates full closure continues for a predetermined time, the output opening detection value of the opening detection device after the lapse of the predetermined time is based on the full closure. There is known a fully closed reference position signal correction device that updates the position (Japanese Patent Laid-Open No. 57-188753).

[0005]

The exhaust gas recirculation valve is most often used in the fully closed position. For example, as shown in FIG. 7, the usage frequency of the exhaust gas recirculation valve when traveling in the LA # 4 mode stipulated in the United States is 55.3% as shown by I in FIG. 7 when the exhaust gas recirculation valve is fully closed, and the remaining 44.7% of the remaining 44.7%. During EGR operation, the usage frequency of the extremely low lift amount of 0 to 0.5 mm is 21.4%, which exceeds 70%, as shown in II. Note that III indicates that the exhaust gas recirculation valve is fully opened and stopped.

Therefore, since the exhaust gas recirculation valve is in a fully closed state in many cases, the wear of the resistor of the opening degree detection device near the fully closed position due to engine vibration is great, and as described above, the lift is extremely low. Since the amount of use of the amount is high, overshooting and undershooting are repeated, so that the resistance of the opening detecting device is often worn near the fully closed position.

Further, the exhaust gas recirculation valve has deposits (deposits of carbon fine particles) attached to the seat due to long-term use, and the manner of the attachment is uneven, and at the fully closed position where the valve body is in close contact with the seat. An error occurs in the fully closed position due to the above-mentioned deposit or the fine dust contained in the exhaust gas being caught.

Therefore, the detected opening value of the exhaust gas recirculation valve opening detection device at the time of the fully closed command is unreliable due to the abrasion of the resistor near the fully closed position, and the value of the fully closed position due to the foreign matter being caught is not enough. Due to the occurrence of an error, the above-mentioned conventional fully closed reference position signal correction device cannot obtain an accurate fully closed detection value, so that the accuracy of the EGR flow rate cannot be ensured, which adversely affects exhaust emission, drivability, and fuel consumption. Cause

The present invention has been made in view of the above points,
An object of the present invention is to provide a fully closed reference position signal correction device for a control valve of an internal combustion engine that solves the above problems by updating the fully closed reference position signal based on the control valve stroke amount and the fully opened position signal at the time of new vehicle. To do.

[0010]

In order to achieve the above object, the present invention, as shown in the principle block diagram of FIG. 1, includes an opening detecting device 11 for detecting the opening of the control valve 10 and first to third parts. It has the calculation means 12, 13 and 14. The first calculating means 12 controls the control valve 1 when the traveling distance is less than a predetermined value.
A stroke amount that is the difference between the fully closed position and the fully open position of 0 is calculated. When the travel distance is equal to or greater than the predetermined value, the second calculating means 13 outputs the fully open position signal extracted from the opening degree detecting device 11 and the first calculating means 12 each time the control valve 10 is instructed to fully open. Calculate the difference from the stroke amount. Third
The calculation means 14 compares the difference value calculated by the second calculation means 13 between the previous full-open instruction and the current full-open instruction, and fully closes the value corresponding to the difference value according to the comparison result. The reference position signal is updated and output.

[0011]

The stroke amount calculated by the first calculating means 12 is a value when the traveling distance is less than the predetermined value when the vehicle is a new vehicle. At this time, the control valve 10 is like a new one, and therefore the accurate stroke amount is calculated. can do. In addition, the control valve 1
Since the frequency of use in the fully open position of 0 is much less than that in the fully closed position, the wear of the resistor when the control valve 10 of the opening degree detection device 11 is fully opened is significantly less than when it is fully closed, and the traveling distance is long. Even if it becomes the predetermined value or more, the deterioration of the fully open position signal is small.

Therefore, according to the present invention, every time the control valve 10 is instructed to be fully opened by the second calculating means 13 and 14, the fully closed reference value is updated from the fully opened position signal and the stroke amount. It is possible to obtain a more accurate fully closed reference position signal than updating the position signal with the detected value of the fully closed position.

[0013]

FIG. 2 shows a schematic system configuration diagram of an internal combustion engine to which the present invention is applied. In the figure, an exhaust gas recirculation valve 20 corresponds to the control valve 10, a diaphragm 21 and a spring 22.
And a needle valve (valve body) 23. Diaphragm 2
1, a spring 22 urges a spring force downward in the figure, one end of a needle valve 23 is fixed to its center, and one end of a rod-shaped body 33 of a lift sensor 30 is fixed. . When the exhaust gas recirculation valve 20 is fully closed, the needle valve 23 is connected to the opening 4 of the EGR gas passage 40 as shown in the figure.
3 is closed.

The lift sensor 30 is the opening detection device 11
The sensor is composed of a resistor 31, a slider 32, and a rod-shaped body 33. A predetermined DC voltage is applied across the resistor 31. Further, the slider 32 is fixed to the rod-shaped body 33 and moves integrally with the movement of the needle valve 23 via the rod-shaped body 33 and the diaphragm 21 to move the resistor 3.
Sliding on 1. As a result, the voltage of the resistance voltage dividing ratio corresponding to the position on the resistor 31, that is, the opening detection voltage of the level corresponding to the position of the needle valve 23 is taken out from the slider 32.

The EGR gas passage 40 communicates with an exhaust manifold (not shown) which is an exhaust passage of the internal combustion engine, and a gas passage 42 which communicates with an intake manifold (not shown) which is an intake passage of the internal combustion engine. The gas passages 41 and 42 are communicated with each other through the opening 43. Further, the opening area of the opening 43 is controlled by the position of the needle valve 23 (that is, the opening area is set according to the opening degree of the exhaust gas recirculation valve 20).

The three-way solenoid valve 50 is composed of a solenoid 51, valves 52 and 53, and has a first port P ₁ communicating with the atmosphere, a second port P ₂ communicating with the exhaust gas recirculation valve 20 and an intake pipe negative pressure. Third port P ₃ communicating
have. The solenoid 51 is an electronic control unit 6 described later.
The drive pulse of 0 or more is energized for a high level period and is de-energized for a low level period.

As a result, when the solenoid 51 is energized, the valve 52 is turned off, the valve 53 is turned on, and the intake pipe negative pressure input to the port P ₃ is supplied to the exhaust recirculation valve 20 via the valve 53 and the port P ₂ . The diaphragm 21 is sucked upward in the figure against the spring force of the spring 22, and the needle valve 23 is moved upward accordingly to open the opening 43.

When the solenoid 51 is not energized, the valve 52 is turned on and the valve 53 is turned off so that the exhaust gas recirculation valve 20 is communicated with the atmosphere through the ports P ₁ , 52 and P ₂ , thereby causing the diaphragm 21 to spring. Two
The spring force of 2 moves downward in the figure, and accordingly, the needle valve 23 is moved downward to close the opening 43. Therefore, the opening area of the opening 43, that is, the opening degree of the exhaust gas recirculation valve 20 changes according to the duty ratio of the drive pulse supplied to the solenoid 51.

The electronic control unit 60 receives the opening detection voltage corresponding to the position of the needle valve 23 of the exhaust gas recirculation valve 20 from the lift sensor 30, and the first to third calculating means 12 to
It is composed of a central processing unit (CPU) 61 for realizing 14 by software processing operation, a memory 62 for storing programs and data, a drive circuit 63 for sending drive pulses to the solenoid 51, and the like.

Next, a fully closed reference position signal correction routine executed by the electronic control unit 60 and realizing the first to third calculating means 12 to 14 will be described. 3 and 4 are flowcharts (No. 1 and No. 2) of the first embodiment of the fully-closed reference position signal correction routine which is an essential part of the present invention. When this routine is started, for example, in a part of the main routine, it is first determined whether the traveling distance is less than a predetermined value (step 101).

Since this predetermined value is set to the maximum value of the mileage in which the vehicle equipped with the internal combustion engine is regarded as a new vehicle, when the mileage is less than the predetermined value, the vehicle is a new vehicle and exhaust gas recirculation is performed. The valve 20 is in a new state, there is no deposit, and the lift sensor 30 has thermal expansion and aging.
It is determined that the resistors 31 are not deteriorated, and the process proceeds to the next step 102. If the mileage is equal to or greater than the predetermined value, it is determined that the vehicle is not a new vehicle and the process proceeds to step 109 in FIG.

In step 102, it is determined whether or not the operating condition is a fully closed condition (eg, deceleration, idle state, etc.) in which EGR is not performed. If the fully closed condition is met, a drive pulse is sent from the drive circuit 63 to the solenoid 51. Then, the solenoid 51 is continuously turned off and the opening 43 is closed by the needle valve 23. Then proceed to step 103,
It is determined whether or not a predetermined time t _{2 has} elapsed from the determination of whether the fully closed condition is satisfied in step 102. This is because the needle valve 23 moves to the fully closed position when the exhaust gas recirculation valve 20 has a certain opening even if the solenoid 51 is started to be de-energized by the electronic control unit 60 because the fully closed condition is satisfied in step 102. This is because there is a physical delay before the end of the process, and it is necessary to consider this physical delay when making a determination.

The predetermined time t ₂ is set to be slightly longer than the time required for the needle valve 23 to complete the movement from the fully open position to the fully closed position, so that the predetermined time t _{2 has} elapsed in step 103. If it is determined that the needle valve 23 has moved to the fully closed position, the process proceeds to step 104, and the output voltage C ₀ of the lift sensor 30 at that time is fetched and stored in the memory 62.

When the conditions of steps 102 and 103 are not satisfied, or when the process of step 104 ends, it is determined whether the operating conditions (for example, at high rotation speed and high load) for fully opening the exhaust gas recirculation valve 20 are reached. If it is determined (step 105) and the full-open condition is not satisfied, this routine is temporarily terminated. If the full-open condition is satisfied, a predetermined time t after the full-open condition is satisfied.
It is determined whether or not _{one has} passed (step 106).

This predetermined time t ₁ is the time from when the energization signal is output from the electronic control unit 60 to the solenoid 51 (after the full open instruction is given) until when the needle valve 23 actually moves to the full open position. It is set to a value slightly larger than the maximum value. Accordingly, when it is judged at step 106 that t> t _1, it is judged that the needle valve 23 is at the fully open position, and at that time, the lift sensor 30 causes the electronic control unit 60 to operate.
The output voltage B ₀ supplied to is taken in (step 10
7) and store it in the memory 62.

Here, the voltage output from the slider 32 of the lift sensor 30 and the needle valve 23 (exhaust gas recirculation valve 20).
The position of has a proportional relationship as shown in FIG. Therefore, in the next step 108, the voltage A indicating the stroke amount a of the needle valve 23 is obtained by subtracting the fully closed detection voltage C ₀ at the new vehicle from the fully opened detection voltage B ₀ at the new vehicle. Also,
This voltage A indicates the originally correct stroke amount when the exhaust gas recirculation valve 20 is in a new state. Note that step 105
If the conditions of No. 106 are not satisfied, this routine is once terminated.

When the process of step 108 is completed or when the traveling distance is determined to be a predetermined value or more in step 101, the process proceeds to step 109 of FIG. 4 under the operating condition (fully open condition) in which the exhaust gas recirculation valve 20 is fully opened. It is determined whether or not there is. When the condition is not fully open, this routine is ended. When the condition is fully open, it is determined whether or not a predetermined time t _{1 has} elapsed since the establishment of step 109 (step 110). If the predetermined time t ₁ has not elapsed, this routine is terminated. When the exhaust gas recirculation valve 20 (needle valve 23) is physically at the fully open position after a lapse of a predetermined time t ₁ after the end, the output voltage B of the lift sensor 30 at that time is fetched (step 111). It is stored in the memory 62.

Next, the voltage B fetched in step 111
Then, the detected voltage Ci at the fully closed position of the exhaust gas recirculation valve 20 this time is calculated by subtracting the voltage A indicating the stroke amount calculated in step 108 and stored in the memory 62 (step 112). That is, even if the traveling distance becomes a predetermined value or more and the exhaust gas recirculation valve 20 changes with age, the use frequency of the fully open condition is low. Therefore, the wear of the resistor 31 at the fully open position is far greater than the wear at the fully closed position. Even if there is a small amount of deposit on the opening 43, there is no effect at the time of full opening, so in step 111 there is little variation, and the full open position detection voltage B corresponding to the environment (resistor temperature, etc.) at that time is small. can get.

Therefore, in step 112, the voltage A indicating the original stroke amount A is subtracted from the fully open position detection voltage B to obtain the accurate fully closed position detection voltage C at that time.
i is obtained. When the calculation of the fully closed position detection voltage Ci in step 112 is completed, the fully closed position detection voltage C _i-1 similarly calculated in step 112 when this routine was last started in step 113 and the current time It is determined whether or not the difference from the fully closed position detection voltage Ci of is within a range from a predetermined lower limit value α to an upper limit value β. This is to prevent erroneous detection when the fully closed position detection voltage Ci (or C _i-1 ) slightly fluctuates due to noise or the like.

Therefore, in step 113, α <C _i-1 -Ci
When <β is determined, it is determined that there is no substantial difference in the fully closed position detection voltage Ci (or C _i-1 ) between the previous time and this time, and this routine is ended as it is. On the other hand, when it is determined in step 113 that the above inequality is not satisfied, the magnitude comparison between the fully closed position detection voltages Ci and C _i-1 is performed (step 114).

When it is determined that C _i-1 > Ci, a predetermined value ΔC is added to C _i-1 to obtain the current fully closed position detection voltage Ci (step 115), and it is determined that C _i-1 ≧ Ci. When you hit C
_The predetermined value ΔC is subtracted from _i-1 to obtain the current fully closed position detection voltage Ci (step 116). That is, the fully closed position detection voltage Ci is C based on the magnitude comparison result of step 114.
In step 115 or 116, the value is updated by adding or subtracting the predetermined value ΔC to or from the previous value C _i−1 so as to approach i.
Is used as the fully closed reference position signal. When this updating process is completed, the next process can be performed, so that the current fully closed position detection voltage Ci is substituted into C _i-1 (step 117), and this routine is completed.

When the traveling distance becomes equal to or greater than the predetermined value, the processing of steps 109 to 117 is periodically performed, and every time the exhaust gas recirculation valve 20 is instructed to be fully opened, the detection voltage Ci serving as the fully closed reference position signal is set. It is updated according to the magnitude comparison result of Ci _-1 and Ci.

As described above, according to this embodiment, the first calculating means 12 is realized by steps 101 to 108 of FIG. 3, and the second calculating means 13 is realized by steps 109 to 112 of FIG. The third calculating means 14 can be realized by steps 113 to 116. As a result, in this embodiment, the fully closed position detection voltage C, which is easily affected by the mounting tolerance of the lift sensor 30, the tolerance of the resistor 31, wear over time, and the deposit, is changed to the fully open position detection voltage B with less variation factors and the new vehicle. Since it is calculated from the difference with the stroke amount detection voltage A at the time, a substantially accurate fully closed position detection voltage C with less variation can be obtained.

Further, since the mounting tolerance of the lift sensor 30 can be sufficiently absorbed, the yield can be improved and the mass production cost can be reduced. Furthermore, according to the present embodiment, it is not necessary to use an expensive resistor 31 for the lift sensor 30, and therefore the cost of the entire device can be reduced.

Next, the second routine of the fully closed reference position signal correction routine
Examples will be described. FIG. 6 shows a flow chart of the main part of the second embodiment of the fully closed reference position signal correction routine.
In the figure, those parts that are the same as those corresponding to the processing steps in FIG. 4 are designated by the same reference numerals, and a description thereof will be omitted. In this embodiment, the steps shown in FIG.
Before 121, the routine is the same as that of the routine of FIG. 3. After the stroke amount detection voltage A is calculated in step 108 of FIG. 3, or when the traveling distance is equal to or more than a predetermined value, the process proceeds to step 121 of FIG. It is determined whether or not the lift amount indicated by the detected voltage is larger than the predetermined value L ₁ .

The predetermined value L ₁ is lower than the fully open position detection voltage, and is set to a certain value equal to or higher than the intermediate position detection voltage between fully open and fully closed, for example. When it is determined in this step 121 that the lift amount> L ₁ , the exhaust gas recirculation valve 20 is forcibly opened (step 122), and then the above-mentioned steps are performed.
The Ci update processing of 110 to 117 is executed. Then, after the processing of step 117, the solenoid 5 is adjusted so that the original output detection voltage of the lift sensor 30 in step 121 can be obtained.
The duty ratio of 1 is controlled (step 123), and this routine ends.

In the first embodiment, the fully closed position detection voltage (fully closed reference position signal) Ci unless the operating conditions are such that the exhaust gas recirculation valve 20 is fully opened when the traveling distance is equal to or greater than a predetermined value.
The update processing is not performed, and the opportunity for learning is small. On the other hand, in the present embodiment, when the opening degree of the exhaust gas recirculation valve 20 is close to full open, the update processing of Ci is forcibly opened and the Ci update processing is performed. More learning opportunities can be provided, and more reliable fully closed reference position signal correction can be performed.

In this embodiment, the exhaust gas recirculation valve 20 is forced.
Set value L of the operating range to be fully opened ₁To a value close to full throttle
By limiting, without degrading drivability
Can be updated.

[0039]

As described above, according to the present invention, when the traveling distance is equal to or greater than the predetermined value, the fully closed reference position is determined from the latest fully open position detection voltage and the signal indicating the original stroke amount without deterioration in a new vehicle. Since the signal is updated, it is possible to obtain a highly reliable fully closed reference position signal corrected in accordance with environmental conditions, as compared with updating the fully closed reference position signal based on the fully closed detection voltage. It has features.

[Brief description of drawings]

FIG. 1 is a principle block diagram of the present invention.

FIG. 2 is a schematic system configuration diagram of an internal combustion engine to which the present invention is applied.

FIG. 3 is a flow chart (No. 1) of a first embodiment of a fully closed reference position signal correction routine which is an essential part of the present invention.

FIG. 4 is a flow chart (No. 2) of the first embodiment of the fully closed reference position signal correction routine which is an essential part of the present invention.

FIG. 5 is a diagram showing a relationship between an opening degree of an exhaust gas recirculation valve and a lift sensor output voltage.

FIG. 6 is a second routine of the fully closed reference position signal correction routine of the present invention.
It is a flow chart of the important section of an example.

FIG. 7 is an explanatory diagram of an example of lift distribution of an exhaust gas recirculation valve.

[Explanation of symbols]

 10 Control Valve 11 Opening Detecting Device 12 First Calculating Means 13 Second Calculating Means 14 Third Calculating Means 20 Exhaust Gas Recirculation Valve 21 Diaphragm 22 Spring 23 Needle Valve (Valve) 30 Lift Sensor 31 Resistor 32 Sliding Child 40 EGR gas passage 43 Opening 50 Solenoid valve 60 Electronic control device

Claims (1)

[Claims] 1. An opening degree detection device for detecting an opening degree of a control valve of an internal combustion engine, and a stroke amount which is a difference between a fully closed position and a fully opened position of the control valve when a traveling distance is less than a predetermined value. When the travel distance is equal to or more than the predetermined value, the full-open position signal extracted from the opening degree detection device and the first calculation means are output every time the control valve is instructed to open fully. The second calculation means for calculating the difference from the stroke amount and the value of the difference calculated by the second calculation means are compared at the time of the last full-open instruction and at the time of the current full-open instruction, and the comparison result is shown. And a third calculating means for updating and outputting a fully closed reference position signal corresponding to the value of the difference.