JPS608445B2 - Characteristic setter for transducer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to transducers for converting mechanical positions into electrical signals, and more particularly to a characteristic setter for presetting standard characteristics of such transducers.

Transducers, which convert the mechanical position of a movable member into an electrical signal, are used in a variety of automatic control equipment.

For example, it is a throttle valve position detector of an automobile engine, or an intake flow rate detector. These transducers consist of potentiometers with a switch responsive to a movable member. A constant voltage is applied across the resistor of this potentiometer, and the potential of the slider varies depending on the position of the slider, that is, the position of the movable member. On the other hand, if the resistance change characteristics of the potentiometer alone are insufficient for the transducer characteristics, the potentiometer is equipped with several intermediate taps and semi-fixed variable resistors are connected to these to correct the resistance change characteristics of the potentiometer. do. In such cases, the resistance value of each semi-fixed variable resistor is determined in advance by calculation according to the output characteristics required of the transducer, but it It is not always easy to know the output characteristics actually required of the transducer and to determine the corresponding amount of correction of the resistance value of the semi-fixed variable resistor. For example, when using a transducer for an intake flow rate detector for a fuel injection device of an automobile engine, it is difficult to know in advance the characteristics required of the transducer when actually installed in the engine. A semi-fixed resistor is installed to adjust the characteristics of the transducer so that the output voltage output from the intake flow rate detector in response to the intake flow rate value is supplied with fuel that achieves the desired engine operating state while observing the operating status of the engine. This adjustment was not easy. In addition, the characteristics required of a transducer differ depending on the engine model, and it is not a good idea from a cost standpoint to prepare a different transducer for each model. Instead, a general-purpose transducer is used with the characteristics modified to suit each model. This is also being done. An object of the present invention is to provide a transducer characteristic setting device for determining in advance the output characteristics actually required when such a transducer is actually used.

The invention will be described in detail below with reference to the drawings.

FIG. 1 shows a transducer portion of a bridging plate type intake gravity detector for detecting the intake air amount of an internal combustion engine. The dam plate 10' rotates about a shaft 12 in response to the air flow as indicated by arrow A in the intake pipe 11. The dam plate 1 is connected to the slider 14 of the potentiometer 13 by a suitable link mechanism.
The slider 14 moves over the resistance RP depending on the position of the dam plate 10. From point 1, No. It is configured to move up to point 9. In this transducer, sufficient output characteristics cannot be obtained only by the resistance change characteristics of the potentiometer 13, so No. No. 1, no. 9
Pull out a tap from each point and connect a semi-fixed variable resistor R to this tap.
,~R9 is connected, and then the semi-fixed variable resistor R,.
R,. are connected. In operation, when a constant voltage UB is applied across the series resistors 15, 16, terminals 17, 1
A voltage U is generated at 8.

Since the slider 14 responds to the dam plate 101, the voltage ratio (U/
UB) and the intake flow rate (Q), in other words, the output characteristics of the transducer are expressed as shown in FIG. Second
The output characteristics shown in the figure vary depending on various conditions such as the type of internal combustion engine. The desired output characteristics are obtained by adjusting the resistance value.

In order to obtain such output characteristics, the resistance value of the half-time constant variable resistor corresponding to the potential at each point 1 to 9 is sequentially adjusted while gradually changing the air volume. Because they are connected in series, if you adjust the resistance value of the corresponding semi-fixed variable resistor to adjust the potential at one point, the potential at other points will also change, making adjustment very difficult and requires skill. It is necessary. Therefore, the present invention provides a characteristic setting device for easily performing such adjustment to obtain desired characteristics.

FIG. 3 shows a characteristic setter according to the invention.

This characteristic setter is a voltage follower V using an operational amplifier.
F, ~VF9. The output terminals of the voltage followers VF, .about.VF9 are connected to points 1 to 9 of the potentiometer 13 via terminals T, .about.L. Voltage follower VF, ~VF
Input terminals 9 are connected to sliders of potentiometers VR, to VR9, respectively. Potentiometer VR. ~VR
9 are connected to positive and negative bus lines 19 and 201 via resistors R2, , R to R29 and R39, respectively. Resistance R2,,
R3, to R29, R39 are potentiometers VR
, ~ The potential that should appear on the slider of VR9 is predicted and the required variable range of the potentiometer is narrowed as much as possible to enable more accurate potential setting. The potentials of the sliders VR, to VR9 are supplied to each point 1 to 9 of the potentiometer 13 without being influenced by each other via the voltage followers VF, to VF9.

A portion 21 surrounded by a dotted line is a position detector of the slider 14, and a rotary switch RS has a fixed contact connected to the terminals T2 to L, respectively. an operational amplifier OP, having an input terminal;

, a light-emitting diode D having a cathode connected to the output terminal of the operational amplifier OP,o via a resistor R,2, and a light-emitting diode D2 having an anode, and the anode and cathode of the light-emitting diode D, ○2 are connected to the positive and negative bus lines. 19,2
01 consists of resistors R, 3, R, and 4 connected to each other. In order to obtain desired output characteristics of an intake flow rate detector of an automobile engine using the above-described characteristic setting device, for example, an intake flow rate detector coupled with this characteristic setting device is mounted on the automobile engine.

Next, the automobile engine is operated. Next, the rotary switch RS of the moving element position detector 21 is placed, for example, at this level. By changing the rotational speed of the engine and the opening degree of the throttle valve, the intake air flow rate changes, and the slider 14 responds accordingly. If the slider 14 is near the tap T3, the light emitting diode D is lit, and if the slider 14 is near the tap T, the light emitting diode D2 is lit. Then, both the light-emitting diodes D, D2 are turned off only when the drinker 14 is exactly above the tap T2. Here, the rotational speed of the engine and the throttle valve function are adjusted so that the light emitting diodes D, D2 are both turned off. By adjusting the variable resistor VR2, the voltage at the tap L changes, and the voltage is transmitted to the slider 14 and output through the output terminal 18 of the intake flow rate detector, thereby changing the mixture ratio of the engine. can. Therefore, the variable resistor VR2 is adjusted to set the desired mixing ratio.
Next, the rotary switch RS of the slider position detection device 21
By sequentially performing the same steps as above for steps 3 to 8, all the sections from tap T2 to tap T8 can be operated at the desired mixing ratio.

Although the slider position detector 21 cannot be used for taps T and T9, it is possible to set the engine speed and throttle valve opening and move the slider 14 near taps T and T9. It is easily inferred that the mixing ratio can be set to a desired mixing ratio using the variable resistors VR and VR2. In this way, the engine can be operated at a desired mixture ratio over the entire range from the minimum value to the maximum intake air amount.

Further, the intake flow rate detector in which the variable resistors VR to VR9 are set in this manner becomes an intake flow rate detector having output characteristics suitable for the engine. Here, Fig. 4a,
The principle by which a desired characteristic can be set using a characteristic setting device will be explained by b.

In the characteristic setter according to the invention, each voltage follower V
The output voltage of F, ~VF9 is EiL or BiH (i=1
, 2, . . . 9), the characteristic setter according to the present invention is represented by an equivalent circuit as shown in FIG. 4a.

The relationship between the output voltage e and the position Q of the slider 14 is expressed as shown in FIG. You can get it. In this way, the characteristics of a large number of mass-produced transducers having the configuration shown in FIG. 1 are sequentially adjusted using the output characteristics as shown in FIG. 2 obtained by the characteristic setting device according to the present invention as standard characteristics.

First, the terminals T, ~ of the characteristic setting device of the present invention shown in FIG.
The potential of the negative bus 201 of L and the positive and negative bus 19, 20
Measure the power supply voltage between. Next, connect terminal 1 in Figure 1.
An arbitrary constant current (for example, about 5 hA) is caused to flow from terminal 5 to terminal e 16 using a constant current source. Next was the ship for mass-produced transducers (Figure 1). Adjust the semi-fixed resistor R so that the potential of the terminal T is the same as the potential of the terminal T of the characteristic setting device (FIG. 3). Similarly, semi-fixed amount anti-R2~
Adjust R9 sequentially and set No. 2～Side. 9 potential to terminal T2
- Make it equal to the potential of T9. Finally, a semi-fixed resistor R,
R,. Adjust. Through the above steps, desired standard characteristics obtained by the characteristic setter according to the present invention can be imparted to mass-produced transducers. The entrusted adjustment work does not require special skill, making the adjustment work very efficient. The output characteristics obtained by the characteristic setting device according to the present invention are recorded in a graph or numerical table, and the output characteristics are reproduced on a mass-produced transducer. This is because the relative potential distribution at each point is already given, so the resistance distribution between each tap of the potentiometer is determined, so the resistance distribution between each tap is determined by calculation, and each mass-produced transducer is You can also adjust the resistance between the taps. On the other hand, when setting the standard output characteristic in the characteristic setting device according to the present invention, each potential of the slider of the potentiometers VR, to VR9 is supplied to each point 1 to 9 of the potentiometer 13 independently of each other. Desired output characteristics can be easily obtained.

Furthermore, since the range of potential variation of the sliders of the potentiometers VR, -VR9 is narrowed by the resistors R2, , R3, to R29, and R39, accurate fine adjustment is possible.

Although the present invention has been described above in the case where it is applied to a transducer for an intake air amount detector using a belly stop plate, the present invention is not limited to such a transducer. It is clear that the characteristic setter according to the invention can be used to set the desired standard characteristics of any transducer.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing a transducer of an intake gravity detector using a dam plate, FIG. 2 is an output characteristic diagram of the transducer of FIG. 1, and FIG. FIGS. 4a and 4b, which are diagrams showing an embodiment, are graphs showing an equivalent circuit and a characteristic change state of the characteristic setting device according to the present invention, respectively.

Explanation of main symbols, 10... Dam plate, 11...
・Intake pipe, 13... Potentiometer, R, ~
R,. ...Semi-fixed variable resistor, VF, ~VF9...
Voltage follower, VR, ~ VR9...potentiometer,
RS...Rotary switch, OP.

...Operation amplifier "D,, D2...Light-emitting diode. Figure 2, Figure 4, Figure 4.

Claims (1)

[Claims] 1. A potentiometer 13 consisting of a resistor RP having a plurality of intermediate taps and a slider 14 that can freely slide on the resistor.
a plurality of voltage dividers VR_1 to VR_9 provided in parallel to each other corresponding to the plurality of intermediate taps; a constant voltage source that applies a constant voltage to both ends of each of the voltage dividers; and a constant voltage source that applies a constant voltage to both ends of each of the voltage dividers. A characteristic setting device for a transducer, characterized in that it comprises voltage followers VF_1 to VF_9 that relay divided voltages to the corresponding intermediate taps. 2. A selection switch means RS that relays any one of the output potentials of the voltage follower, and an operational amplifier UP_1_0 that outputs a voltage according to the difference between the potential relayed by the selection switch means and the potential of the slider. , a slider position detection device 21 comprising light emitting diodes D_1, D_2, one of which emits light according to the output voltage of the operational amplifier. Characteristic setting device for transducers.