JPS5893936A - Throttle opening sensor for internal-combustion engine - Google Patents

Abstract

PURPOSE:To reduce the influence onto a basic pulse due to the characteristic error of a sensor in the small valve opening region, by constructing such that the increasing rate of an output signal level in the low opening region of a throttle valve will be higher than the increasing rate in the high opening region of the throttle valve. CONSTITUTION:A resistor board 6 and a conductor board 7 are formed into an arch around a rotary shaft 4 on one face of an insulated substrate 5 secured to a case, while sliding chips 8, 9 fixed to rotary shaft 4 are contacted electrically with each board 6, 7 to constitute a throttle opening sensor. Here the width of the resistor board 10 is not constant but become wider gradually toward the sliding direction of the sliding chip 8. Since the resistance of the resistor board 10 per unit length will decrease as the width of the resistor board 10 increases, the output voltage of the throttle opening sensor increases logarithmically thereby the increasing rate in the small opening region of the throttle valve will be higher than that in the high increasing rate region.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a throttle opening sensor for an internal combustion engine equipped with an electronically controlled fuel injection device.

In an internal combustion engine equipped with an electronically controlled fuel injection device, various engine parameters are detected so that the engine always performs proper combustion. One of the engine parameters is the opening of the throttle valve installed in the intake air passage of the internal combustion engine, and the throttle opening sensor uses a potentiometer etc. to generate an output signal at a level corresponding to the opening of the throttle valve. be.

FIG. 1 is a schematic diagram showing a conventional example of a throttle opening sensor using a potentiometer. In FIG. 1, 1 is a case forming a potentiometer chamber 2. In FIG. A bearing 3 is fitted into the case 1, and a rotating shaft 4 coupled to a throttle shaft (not shown) of a throttle valve is rotatably supported by the bearing 3. In the potentiometer chamber 2, an insulating substrate 5 is fixed to a case l, and on one surface of the insulating substrate 5, a resistance plate 6 and a conductive plate 7 are formed in an arc shape with the rotation shaft 4 at the center. Sliders 8 and 9 fixed to one end of the rotating shaft 4 are in contact with the resistance plate 6 and the conductive plate 7, respectively. The sliders 8 and 9 are electrically connected to each other.

In this configuration, a voltage VB is applied between both ends of the resistance plate 6, and the rotation shaft 4 is applied depending on the opening degree of the throttle valve.
When the slider 8 rotates, the slider 8 moves in contact with the surface of the resistance plate 6, and the slider 9 moves in contact with the surface of the conductive plate 7. The potential of the slider 8 becomes a divided voltage of the voltage VB at the contact position of the slider 8 to the resistance plate 6, and the voltage is applied from the slider 8 to one end of the conductive plate 7 and the resistance plate 6 via the slider 9. This detected voltage becomes the output voltage. The output voltage of the throttle valve/degree sensor is
As shown in the figure, it changes linearly with the throttle valve opening.

By the way, in electronically controlled fuel injection systems, the basic pulse width of 7 pulses corresponding to the basic injection amount is usually calculated from the engine speed and intake air amount, but the intake air amount is calculated from the opening degree of the throttle valve. Because it can be estimated, a throttle opening sensor is sometimes used without using an intake air amount measuring device such as an air flow meter. When calculating the basic pulse using the throttle opening sensor in this way, if the engine speed is kept constant, the basic pulse width will change in the small range of throttle valve opening as shown in Figure 3. The rate is large.

However, in conventional throttle opening sensors, the rate of increase in the output voltage level with respect to the throttle valve opening is always constant, so even small characteristic errors (variations) in the region of small throttle valve opening will cause the fundamental pulse to change. There was a problem in that it had a large negative impact on calculations.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a throttle opening sensor that can suppress the influence of its own characteristic errors on the basic width of the throttle opening.

The throttle opening sensor according to the present invention is configured such that the rate of increase in the output signal level in a region where the opening of the throttle valve is small is higher than the rate of increase in the output signal level in a region where the opening of the throttle valve is small. ing.

Embodiments of the present invention will be described below with reference to FIG.

In FIG. 4, the same parts as those in FIG. It gradually becomes wider in the sliding direction of the slider 8 when the valve is opened. The rest of the structure of the flow opening sensor according to the present invention is the same as the conventional example shown in FIGS. 1(α) and (h).

In the throttle opening sensor according to the present invention having such a configuration, the wider the width of the resistor #100, the smaller the resistance value of the resistor plate 10 per unit length. Therefore, when the power supply voltage VB is supplied as shown in Fig. 4, the output voltage of the throttle opening sensor increases as the throttle valve opens, changing logarithmically as shown in Fig. 5. The rate of increase in the region becomes larger than in the region of large.

As a result, in the electronically controlled fuel injection system using the throttle opening sensor according to the present invention, when the engine speed is constant, the basic pulse width and the pulse width are determined by the throttle opening sensor as shown in FIG. can be changed approximately proportionally to the output voltage level.

Now, as a method of calculating the basic angle using the output signal of the throttle opening degree sensor 11, the opening degree θ of the throttle valve is supplied to the input terminal of the throttle opening degree sensor 11 as shown in FIG. A conceivable configuration is that the output voltage v8 of the throttle opening sensor 11 is supplied to the basic pulse calculation circuit 12 and the basic /f pulse is output.

Here, if the input/output characteristics of the conventional throttle opening sensor 11 are expressed as a function f1 (θ), and the input/output characteristics of the conventional basic pulse calculation circuit 12 are expressed as a function f2 (V8), then the basic pulse obtained from the conventional device Pulse width t2. can be expressed by the following equation. (However, it is assumed that the engine speed is constant.) tPl-f2 (■8>=12(f, (θ))...
...(1) Next, the input/output characteristics of the throttle opening sensor 11 according to the present invention are expressed as a function! 11(θ), and if the input/output characteristics of the basic pulse calculation circuit 120 in the device of the present application are expressed by a function g2(Vs), the basic pulse pulse width t,2
is 'p2''g2(Vs)-g2(gl(θ))...
...(2). A fundamental pulse 1P obtained by equations (1) and (2).

t must always be equal (t6.mit, 2)
.

2 Therefore, by differentiating equations (1) and (2) with respect to the opening degree θ, we get
dt −−f2′(v8)・f1′(θ) dθ Ichiko−y2′(Vs)・l,′(θ)・・・・・・(3
). By the way, fl(θ) represents the input/output characteristics shown in FIG. 2, and (θ represents the human output characteristics shown in FIG. 5, so f1'(θ)<!11'(θ)...・・・
...(4). Therefore, from equations (3) and (4), f2' (■8) and g2' (■8) ・
...(5).

On the other hand, the output voltage displacement of the throttle opening sensor 11 is ΔV
8, in the case of each conventional input/output characteristic, the displacement Δ'p1 of the basic pulse width t is expressed by the following equation.

ΔtP1=f2'(Vs)·ΔV8·---(6) Furthermore, the displacement ΔtP2 when using the throttle opening sensor according to the present invention is expressed by the following equation.

ΔtP2-g2'(vs)・Δ■8...
...(7) Therefore, from equation (5), Δl, 1>Δt, 2...
(8) Therefore, compared to the conventional case, the effect on the basic torque due to the characteristic error of the throttle opening sensor in the region where the opening of the throttle valve is small becomes smaller.

Note that the throttle opening sensor of the present invention is not limited to the above-mentioned embodiments;
The 75E throttle valve 13 may be interlocked with the rotation of the throttle shaft 14 via forces A 15 and 16. In this case, a cam 1. as shown in FIG. 8(h).
Due to the combination of 5 and 16, the rotating shaft 4 rotates more in the region where the opening of the throttle valve 13 is small than in the region where the opening is large, so the input/output characteristics of the throttle opening sensor are as follows.
It will be similar to the figure.

In FIG. 8, numeral 17 is an intake pipe, and numeral 18 is a throttle opening control body having input/output characteristics similar to conventional ones.

As described above, according to the throttle opening sensor according to the present invention, the rate of increase in the output signal level in the region where the opening of the throttle valve is small is higher than the rate of increase in the output signal level in the region where the opening of the throttle valve is small. This makes it possible to reduce the influence on the basic distortion caused by the characteristic error of the throttle opening sensor in a region where the opening of the throttle valve is small compared to the conventional case.

[Brief explanation of drawings]

Fig. 1 (α) is a schematic cross-sectional view showing a conventional example of a throttle opening sensor, Fig. 1 (h) is an illustration of the section A-A in Fig. 1 (a), and Fig. 2 is a diagram of the section A-A in Fig. Throttle opening sensor (Figure 5 shows the input/output characteristics of the throttle opening sensor in Figure 4, and Figure 6 shows the basics when using the throttle opening sensor in Figure 4) The input/output characteristic diagram of the pulse calculation circuit, Figure 7 shows the throttle opening sensor and the basics! FIG. 8(α) is a schematic diagram showing another embodiment of the present invention, and FIG. 8(b) is a diagram showing a combination of the cams shown in FIG. 8(α). Explanation of symbols of main parts ■... Case 4... Rotating shaft 5... Insulating board 6, 10... Resistance plate 7... Continuity plate 8, 9... Slider 13... Throttle valve 15, 16...Cam applicant Japan Electronics Co., Ltd. agent Patent attorney Motohiko Fujimura/Fig. 2I Throttle valve F#! Skin 4ζ Otsu Shiukuro ηW pressure melon 7 figure

Claims (2)

[Claims] (1) A throttle opening sensor that generates an output signal according to the opening of a throttle valve provided in an intake air passage of an internal combustion engine, the output being in a region where the opening of the throttle valve is small. A throttle opening sensor characterized in that the rate of increase in the signal level is greater than the rate of increase in the output signal level in a region where the opening of the throttle valve is large. (2) The throttle opening sensor according to claim 1, wherein the output signal level changes logarithmically with respect to the opening of the throttle valve.