JPS63247610A - Detector for throttle valve opening degree of internal combustion engine - Google Patents

Abstract

PURPOSE:To obtain stable opening degree detection accuracy over the entire opening degree range by performing learning operation in such a direction that a step in detected value generated by the switching of a valve opening degree detecting means is eliminated when the varying speed of a throttle valve opening degree is smaller than a specific value. CONSTITUTION:Output voltages VS1 and VS2 from 1st and 2nd potentiometers of a throttle sensor S are inputted to a controller 21 to retrieve the learnt correcting value DELTAVS of the voltage VS2 stored in a RAM. For example, when VS1<4.5V, the throttle valve opening degree detected value alpha1 is operated. Then the varying speed of the throttle valve opening degree is operated as the difference between the voltage VS1 which is inputted currently and the last input VS1 and when the difference is smaller than the specific value, a throttle valve opening degree detected value alpha2 is operated from the voltage VS2. Then when alpha1>alpha2, the correcting value DELTAVS is increased by a specific quantity and when alpha1<alpha2, the value is decreased by a specific quantity; when alpha1=alpha2, the opening degree alpha1 is set in a register without being corrected. Thus, the correcting value DELTAVS which is corrected and updated is stored in a RAM, so the reliability of learning is high.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a device for detecting the throttle valve opening of an internal combustion engine.

<Prior Art> Some internal combustion engines are equipped with an electronically controlled fuel injection device in which basic fuel injection 'it'rp is set based on throttle valve opening α and engine speed N. .

This device is equipped with a potentiometer-type throttle sensor that detects the throttle valve opening α.
In this case, in the low opening range, the deviation of the intake air flow rate relative to the opening detection error becomes large, so some systems have separately provided a potentiometer that detects only the low opening range to further improve detection accuracy.

That is, as shown in FIG. 5, the first resistor 11 for small opening detection
and a second resistor 12 for large opening detection are connected in parallel, and a constant voltage is applied to these parallel circuits.

Further, an arm 13 made of an insulating member connected to a rotary wheel of the throttle valve has a first brush 15 that slides on the first resistor 11 and the first conductive plate 14 at the same time, and a first brush 15 that is in sliding contact with the first resistor 11 and the first conductive plate 14 at the same time.
and a second brush 17 which is in sliding contact with the second conductive plate 16 at the same time are provided, and these form two sets of potentiometers, one for detecting the booth degree and the other for detecting the large opening degree.

Then, in conjunction with the change in the opening degree of the throttle valve, the arm 13
When the throttle valve rotates around its base end, in the region where the throttle valve opening is small (0 to 22.5"), the electric current from the first conductive plate 14, which is electrically connected to the first brush 15 that slides on the first resistor 11, is Output voltage ■, 1 is 0.5 to 4.5 as shown in Figure 4
from a second conductive plate 16 electrically connected to a second brush 17 that changes linearly in the range of The output voltages (1) and (2) vary linearly in the range of 0.5 to 4.5 (2).

The two types of output voltages Vs+ and V3z are input to a control device (not shown) consisting of a microcomputer, etc., and the control device controls the valve opening degree as shown in FIG. 6 according to these output voltages Vs+, v, and □. Decide according to the flowchart.

That is, in step 1 (denoted as S in the figure), the output voltage VS
+ is A/D (analog-digital) converted and read as a digital value.

In step 2, it is determined whether VS+ is 4.5v or more.

When it is determined that v, .

Also, if it is determined that VS+≧4.5, step 4
Then, the output voltage VSt is A/D converted and the digital value is read.

Next, in step 5, the throttle valve opening degree α2 is calculated as a function of VSZ.

<Problems to be Solved by the Invention> However, in this type of throttle valve opening detection device, the throttle sensor is attached to the throttle valve based on a potentiometer for detecting small openings that emphasizes detection accuracy. However, due to manufacturing variations in the sensor, the output voltage of the two potentiometers V,...
If the correspondence between V and □ deviates, the output voltage V! is used to calculate the valve opening degree. At the time of switching the use of l+ VSZ (22.5° in the above example), a step occurs in the calculated value of the valve opening, which in turn adversely affects fuel injection amount control etc. based on the detected valve opening. For example, one problem is that during acceleration/deceleration operation, a difference in torque occurs, causing shock and deterioration of exhaust characteristics.

The present invention was made by focusing on such conventional problems, and eliminates the difference in detection values due to manufacturing variations in the throttle sensor section through learning, thereby achieving stable opening detection accuracy over the entire opening range. An object of the present invention is to provide a throttle valve opening detection device for an internal combustion engine that can obtain the following.

(Means for Solving the Problems) Therefore, as shown in FIG. The valve opening detection means and the valve opening in at least the large opening area detected by the first valve opening detection means and the large valve opening area other than the area detected by the same detection means. a second valve opening degree detection means for detecting the change rate of the throttle valve opening degree; a valve opening degree change rate detection means for detecting the rate of change in the throttle valve opening degree; and a valve opening degree detection value detected by the second valve opening degree detection means. at least a portion of the valve opening range detected by both the first valve opening detection means and the second valve opening detection means; When the speed of change in the throttle valve opening detected by the valve opening change speed detecting means is less than or equal to a predetermined value, the detected value by the second valve opening detecting means is converted into a learning correction stored by the learning correction value storage means. Learning correction value correction that compares the value corrected by the value and the value detected by the first valve opening detection means, and corrects and rewrites the learning correction value stored in the learning correction value storage means so as to bring the former closer to the latter. and in the valve opening range detected by the first valve opening detection means, the detected value is selected as the throttle valve opening, and in other valve opening ranges, the detected value is selected as the throttle valve opening. and valve opening detection value selection means for selecting, as the throttle valve opening, a value obtained by correcting the detected value using the learning correction value stored in the learning correction value storage means.

Effect> In a region where the throttle valve opening is small, the valve opening detected by the first valve opening detection means is selected as the valve opening detection value by the valve opening detection value selection means.

In addition, in a region where the throttle valve opening is large other than that detected by the first valve opening detection means, the valve opening detected by the second valve opening detection means is determined by the learning correction value stored in the learning correction value storage means. The corrected value is selected as the valve opening detection value by the valve opening detection value selection means.

On the other hand, at least a part of the region where the valve opening degree is detected by both the first valve opening degree detection means and the second valve opening degree detection means, and
When the rate of change in the throttle valve opening detected by the valve opening rate change detection means is less than a predetermined value, the learning correction value correction means stores the valve opening detected by the second valve opening detection means in the learning correction value storage means. The value corrected using the stored learning correction value is compared with the valve opening detected by the first valve opening detecting means, and the learning correction value is corrected to bring the former closer to the latter. The learning correction value stored in the learning correction value storage means is rewritten.

<Example> An embodiment of the present invention will be described below based on the drawings.

In FIG. 2 showing the configuration, the throttle sensor S is the same as the conventional example shown in FIG. 5, so the same reference numerals are given.

The output voltages V311 and Vsz from the first and second potentiometers of the throttle sensor S are input to a control device 21 for fuel injection control that has a built-in microcomputer, and the control device 21 performs the following control based on the output voltage v, 1°VSZ. The throttle valve opening degree is detected in this manner, and the fuel injection amount is calculated based on this detected value.

This throttle valve opening detection routine will be explained according to the flowchart of FIG.

In step 11, the digital value of the output voltage VS+ and the digital value of the output voltage VSZ are read.

In step 12, the learning correction value Δ■3 of the output voltages ■ and χ stored in the RAM is retrieved.

In step 13, it is determined whether the output voltage ■□ has reached the upper limit value of the valve opening detection value, 4 or 5■, and Via<
In the case of 4.5V, learning described later is performed prior to detecting the valve opening degree.

In step 14, the throttle valve opening detection value α is calculated from the output voltage VS+ using the following equation.

α+ − to + (Via 0.5) In step 15, the rate of change of the throttle valve opening is determined by comparing the output voltage VS+ input this time in step 11 and the output voltage VSt input last time.
It is calculated as the difference ΔVS+. The function of step 15 corresponds to a valve opening change rate detection means.

In step 16, Δv calculated in step 15 is calculated.

It is determined whether the rate of change of the throttle valve opening is less than or equal to a predetermined value depending on whether or not is less than or equal to a predetermined value. For example, the output voltage V! If it takes 1 ms to A/D convert l, vs □, the detection error of the valve opening degree with respect to this time delay is 0.
In order to make it 1° or less, the rate of change in the opening degree of the throttle valve needs to be 0.1°/ll5 or less. That is 9
00a+s, which is less than the speed required to change from fully closed to fully open, and the predetermined value to be compared with the ΔVS+ is set to a voltage difference (-0,004V) corresponding to this speed.

If the rate of change in valve opening is greater than this, the reliability of performing learning to eliminate the difference in the two types of detected values will decrease, so proceed to step 17 without performing learning, and proceed to step 1.
The throttle valve opening α1 calculated in step 4 is selected as the detected value and set in the register.

If it is determined in step 16 that ΔVS+ is less than or equal to the predetermined value, the process proceeds to step 18 and subsequent steps to perform the learning described above.

In step 1, the throttle valve opening detection value α2 is calculated from the output voltage Vat using the following equation.

txt'-kl (Vsz+ΔVs O, 5)
-4, (Vs, +ΔVs O, 5) However, k,
is a constant corresponding to the slope of each characteristic in FIG.

In step 19, the magnitude relationship between the two valve opening detection values α1 and α2 calculated in step 14.15 is compared.

Then, when α, > α2, proceed to step 2o and increase the learning correction value Δ■3 by a predetermined amount (1 in the embodiment), and when α, > α2, proceed to step 21 and decrease Δ■3 by a predetermined amount. After that, if α1=α2, the process proceeds to step 17 without making such correction, and the throttle valve opening degree α1 is set in the register.

The learning correction value Δ■s modified and updated in this manner is stored in a RAM serving as a learning correction value storage means.

On the other hand, when it is determined in step 13 that VSI≧4.5■, the process proceeds to step 22, and the output voltage VSZ
and the learning correction value ΔV, the throttle valve opening detection value is calculated using the following equation.

αz −kg (Vsz+Δv, −0,5) Next, the process proceeds to step 23, and the throttle valve opening detection value α2 calculated in step 22 is set in the register.

In this way, in step 20 or step 21, the learning correction value Δ■5 is revised and updated so that the detected value α based on the second potentiometer approaches the detected value α based on the first potentiometer, and As determined in step 16, the above learning is performed only when the rate of change in the valve opening degree is low and the detection error is small, so the reliability of the learning is high.

In this way, the highly reliable learning correction value Δ■.

Since α8 is calculated in step 22 using
It is possible to continuously and smoothly change the value detected by the second potentiometer without causing a step when switching to the value detected by the second potentiometer, and the learning is performed in accordance with the first potentiometer, which is originally set to high accuracy. Therefore, detection accuracy on the high opening side can also be improved.

Therefore, acceleration/deceleration shock during acceleration/deceleration operation and deterioration of exhaust characteristics can be suppressed.

In this embodiment, the first resistor 11. The first potentiometer consisting of the first conductive plate 14 and the first brush 15 and the function of step 14 constitute the first valve opening detection means, and the second
Resistance 12. Second conductive plate 16. The second potentiometer consisting of the second brush 17 and the function of step 18.22 constitute a second valve opening detection means.

Further, steps 16 to 21 constitute a learning correction value modification means, and steps 13 and 17.23 constitute a valve opening detection value selection means.

In this embodiment, the second potentiometer can also detect the entire small opening region that can be detected by the first potentiometer, and learning is performed in this entire region, but learning is performed only in the vicinity of the switching point. Good too.

(Effects of the Invention) As explained above, according to the present invention, learning is performed in the direction of eliminating the difference in detected values caused by switching between two types of valve opening detection means for small opening detection and large opening detection. This learning is performed only when the rate of change in the valve opening is small, increasing the reliability of the learning. This improves the accuracy of air-fuel ratio control, etc. by detecting the throttle valve opening, and improves the accuracy of air-fuel ratio control during acceleration and deceleration. It can reduce shock and improve exhaust characteristics.

[Brief Description of the Drawings] Fig. 1 is a block diagram showing the configuration of the present invention, Fig. 2 is a block diagram of an embodiment of the present invention, and Fig. 3 shows a throttle valve opening detection routine of the same embodiment. Flowchart, FIG. 4 is a graph showing the throttle valve opening detection characteristics of the same embodiment as above,
FIG. 5 is a configuration diagram showing an example of a throttle sensor, and FIG. 6 is a flowchart showing a conventional throttle valve opening detection routine. 11...First resistor 12...Second resistor 14.
...First conductive plate 15...First brush 16...
・Second conductive plate 17...Second brush Patent applicant Japan Electronics Co., Ltd. Representative Patent attorney Fujio Sasashima Figure 2 Figure 4, TNT pressure VS Figure 5 Figure 6

Claims (1)

[Scope of Claims] First valve opening detection means for detecting a valve opening in a region where the opening of a throttle valve installed in an intake passage of an internal combustion engine is small; and detection by the first valve opening detection means. a second valve opening detection means for detecting the valve opening in at least a large opening region of the valve opening region detected by the throttle valve opening and a region in which the valve opening is large other than that detected by the detection means; Valve opening change speed detection means for detecting a change speed; Learning correction value storage means for rewritably storing a learning correction value for correcting the valve opening detection value detected by the second valve opening detection means. and a throttle valve opening detected by the valve opening change rate detection means in at least a part of the valve opening range detected by both the first valve opening detection means and the second valve opening detection means. When the rate of change of is less than a predetermined value, the value detected by the second valve opening detection means is corrected by the learning correction value stored by the learning correction value storage means and the value detected by the first valve opening detection means. learning correction value correction means for correcting and rewriting the learning correction value stored in the learning correction value storage means so as to bring the former closer to the latter; and a valve opening detected by the first valve opening detection means. In the valve opening range, the detected value is selected as the throttle valve opening, and in other valve opening ranges, the detected value detected by the second valve opening detection means is used as the learning correction value stored in the learning correction value storage means. 1. A throttle valve opening detection device for an internal combustion engine, comprising: valve opening detection value selection means for selecting a corrected value as a throttle valve opening.