JP2584248Y2 - Analog fuel measurement device - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an analog fuel measuring device for measuring a liquid level in a fuel tank of an automobile, for example.

[0002]

2. Description of the Related Art As shown in FIG. 3, a conventional analog fuel measuring device comprises an input signal calculating circuit 1, a driving signal calculating circuit 2, a driving circuit 3, and a cross-coil meter unit 4. Will be described respectively.

First, the input signal calculation circuit 1 includes an averaging circuit 11, a period measurement circuit 12, and a control angle calculation circuit 13, and the averaging circuit 11 responds to a measured amount such as a liquid level in a fuel tank. Frequency signal f _av whose frequency changes is sampled at certain intervals and averaged frequency signal f _av
Is output. In period measurement circuit 12 obtains the averaged frequency signal f _av than the period measured period of the averaged frequency signal f _av (T). Further, the control angle calculation circuit 13 calculates the cycle measurement value (T = 1 / f) from the cycle measurement circuit 12 at the preceding stage.
_av ) is converted into a movable magnet rotation control angle (hereinafter abbreviated as a pointer swing angle) signal (rotation control angle signal) a (see FIG. 4A) and output.

The drive signal operation circuit 2 comprises an approximate sine wave generation circuit 21, an approximate cosine wave generation circuit 22, and a polarity switching circuit 23.
The circuit 23 is composed of, for example, a microcomputer. Both the approximate sine wave generation circuit 21 and the approximate cosine wave generation circuit 22 receive the pointer shake angle signal a from the input signal calculation circuit 1 and perform signal processing such as angle comparison and phase shift based on the pointer shake angle signal a. PWM signals b and c which have a phase difference of 90 ° from each other and change with the characteristics of a pentagonal wave according to the angle value of the signal a.
(See FIG. 4B). The polarity switching circuit 23 generates an approximate sine wave generating circuit 2 based on the signal a.
1 and the output signal b from the approximate cosine wave generation circuit 22,
It outputs polarity switching signals d and e (see FIG. 4C) for polarizing c.

The driving circuit 3 comprises two output circuits 31 and 32. Each of the output circuits 31 and 32 is a bidirectional switch circuit composed of, for example, a transistor 9, and includes an approximate sine wave generating circuit 21 and an approximate cosine wave generating circuit. Circuit 22
Output signals b and c are respectively current amplified,
The output signals b and c are polarized based on the polarity switching signals d and e to output two types of drive signals f and g (see FIG. 42). The cross-coil instrument unit 4 includes a drive circuit 3
, And a pair of coils 41 and 42 arranged at an angle of 90 ° to each other and rotatable under the magnetic action of the pair of coils 41 and 42. The movable magnet 43 is provided with two poles and magnetized.

In addition, reference numeral 5 denotes a constant voltage power supply for converting the output voltage of the power supply 6 to a constant voltage, and supplies a constant voltage of 5 V to the drive signal operation circuit 2. Similarly, a constant voltage power supply 7 converts the output voltage of the power supply 6 to a constant voltage, and supplies a constant voltage of 8 V to the drive circuit 3.

FIG. 5 is a cross-sectional view showing a cross-coil instrument unit. In the figure, reference numerals 41 and 42 denote a pair of coils wound so as to cross each other, and 43 denotes a movable magnet magnetized with two poles. , 44 are the movable magnets 4
The pointer shaft penetrates the center of 3 and is integrally attached to the movable magnet 43, 45 is a pointer attached to the tip of the pointer shaft 44, and 46a and 46b are rotatably holding the movable magnet 43 and the pointer shaft 44. Upper and lower housings made of non-magnetic material such as plastic.

Reference numeral 47 denotes a cup-shaped magnetic shield case made of a soft magnetic material, which is disposed so as to protect the outside of the coils 41 and 42, and is fixed to a column of the lower housing 46b by screws 47a. A support arm 49 integrally extending from a column of the upper housing 46a.
Are fixed by screws 49a. In addition,
The configuration is such that external magnetism does not affect the movable magnet 43 by the action of the magnetic shield case 47.

Further, such a cross-coil instrument unit 4 is of a needle setting type. That is, the needle setting method is such that the pointer 2 moves only when a driving force acts on the movable magnet 43, and stops when the driving force is lost when the driving force is lost. Therefore, as a condition for establishing the needle pointer type indicator, the roundness of the magnetic shield case 47 is improved so that a force other than a driving force due to a change in measured value does not act on the movable magnet 43. Also, the movable magnet 43
And the balance of the pointer shaft 44 is good.

[0010]

Since the conventional analog fuel measuring apparatus is constructed as described above, as shown in FIG. 6, for example, the remaining fuel in the fuel tank is reduced to 1/3 of the fuel tank capacity. If refueling is performed in a certain state, since the cross-coil instrument unit 4 is a needle setting type, even if the ignition switch (switch) is turned off, a value of 1/3 of the fuel tank capacity is indicated. In this state, if the fuel tank is full and the ignition switch is turned on, the pointer 45 of the cross-coil instrument unit 4 once moves largely in the empty direction (EMPTY) and then moves to the predetermined (FULL) level.
Specify the value of This is because, when the ignition switch is turned on, there is no initial data in the averaging circuit 11, so that the average value sampled at regular intervals becomes zero. In this way, the pointer 45 after refueling moves incomprehensibly,
There were problems such as giving the user distrust.

This invention has been made in order to solve the above-mentioned problems, and an analog fuel measurement method in which an initial value is given to an averaging circuit so that the movement of the pointer after refueling does not cause distrust. The aim is to obtain a device.

[0012]

The analog fuel measuring device according to the present invention corresponds to a half of the measuring range of the averaging circuit only for a predetermined time after returning from a switch for opening and closing the entire device .
In which it gave that initial value.

[0013]

The analog fuel measuring device in this invention is
Since an initial value corresponding to a half of the measurement range is given to the averaging circuit, the average value sampled by the averaging circuit becomes ス イ ッ チ of the measurement range after the switch is restored. The cross-type instrument unit is indicated for a predetermined time.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. In the figure, the same parts as those shown in FIG. 2 which is the related art are denoted by the same reference numerals, and the overlapping description will be omitted. FIG. 1 is a block diagram showing an analog fuel measuring apparatus according to an embodiment of the present invention.
0 is 1/1 of the measurement range of the liquid level gauge of the fuel tank only for a predetermined time after the ignition switch is returned to the averaging circuit 11a.
This is a frequency signal as initial data (initial value) corresponding to 2, and the other configuration is the same as that shown in FIG.

Next, the operation will be described. FIG. 2 is an explanatory diagram showing the output of the averaging circuit according to one embodiment of the present invention, and the operation will be described based on the drawing. For example, if refueling is performed in a state where the remaining fuel in the fuel tank is 1/3 of the fuel tank capacity, the cross-coil instrument unit 4 is a needle-pointing type, so even if the ignition switch (switch) is turned off, The value indicates 1/3 of the tank capacity.
In this state, if the fuel tank is filled with the fuel and the ignition switch is turned on (returned), the averaging circuit 11a outputs 1/1 / x of the measurement range of the liquid level gauge of the fuel tank only for 0 to tx time.
2, the cross-coil instrument unit 4 moves in the direction corresponding to one half of its measurement range without moving in the empty direction (ENPTY). Further, after turning on the ignition switch, t
After x time, the value sampled and averaged by the averaging circuit 11a becomes the data of the actual measurement value, so the cross-coil instrument unit 4 indicates a predetermined (FULL) value.
Note that the reason why the output of the averaging circuit 11a falls after the time tx is that fuel is consumed by the engine such as a vehicle.

The reason why the initial data is set to の of the measurement range is to reduce the difference between the initial data and the actual measurement data,
This is for reducing the sense of discomfort to the instruction of the pointer 45. That is, in general, when the remaining fuel becomes less than half of the fuel tank, the fuel is often replenished to fill the tank. In this case, the indication of the pointer 45 does not move in the empty direction, and This is because, when there is more than half of the fuel tank, even if refueling is performed, the difference between the initial data and the actually measured data can be small, and the movement of the pointer 45 in the empty direction can be small.

[0017]

According As described above, according to the invention In this invention, the averaging circuit having a predetermined time only the measurement range after the switch return 1 /
Since the initial value equivalent to 2 is provided , when the fuel is replenished when the remaining fuel amount is less than 1/2 of the measurement range, the indication of the pointer is smoothly moved to the actual measurement value without moving in the sky direction. Follow-up, and even when refueling when the fuel level is more than half of the measurement range, the difference between the initial value and the actual measurement value can be small, the indicator in the empty direction can be small, and the switch returns. There is an effect that an analog fuel measuring device that gives a sense of security to the movement of the pointer afterward can be obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an analog fuel measuring device according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an output of an averaging circuit according to one embodiment of the present invention;

FIG. 3 is a block diagram showing a conventional analog fuel measuring device.

FIG. 4 is a signal waveform diagram of the components shown in FIG.

FIG. 5 is a cross-sectional view showing a conventional cross-coil instrument unit.

FIG. 6 is an explanatory diagram showing an output of a conventional averaging circuit.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 input signal calculation circuit 2 drive signal calculation circuit 3 drive circuit 4 cross-coil instrument unit 5, 7 constant voltage circuit 11 a averaging circuit 21 approximate sine wave generation circuit 22 approximate cosine wave generation circuit 41, 42 coil 43 movable magnet

Claims (1)

(57) [Scope of request for utility model registration] 1. An input signal operation circuit (1) for averaging a frequency signal according to an amount to be measured by an averaging circuit and obtaining a rotation control angle from the averaged frequency signal, and two waveform generation circuits (1). 21 and 22), the signal processing is performed based on the rotation control angle signal by the drive signal calculation circuit (2), so that the drive signal calculation circuit (2) has predetermined phase angles with each other and changes in accordance with the value of the rotation control angle signal. A driving circuit (3) for outputting two kinds of driving signals to be driven, and a movable magnet (43) magnetized by a pair of coils (41, 42) interposed by the two kinds of driving signals and magnetized in two poles. In an analog fuel measuring device including a cross-coil meter unit (4) to be rotated and a constant voltage circuit (5, 7) for supplying a constant voltage to the drive signal calculation circuit and the drive circuit, the entire device is opened and closed. The averaging circuit (11a) corresponds to １ ／ of the measurement range only for a predetermined time after the switch returns .
It gave initial value analog fuel measuring device according to claim that.