JPS62215831A - Liquid-level meter corrected in shape of container - Google Patents

Abstract

PURPOSE:To obtain a liquid-level meter of which the error due to the shape of fuel tank is corrected, by setting the width of a resistor membrane wire to the width inversely proportional to the cross-sectional area at the internal height of a container. CONSTITUTION:A connector 2 taking out a signal to the outside is fixed to a flange 1 and the lead terminal 3 from said connector 2 is connected to a resistor plate 6 for measuring a level through a lead wire 12 in a state insulated from the flange 1. A fine wire-shaped resistor membrane is formed to the surface of the resistor plate 6 and a fine wire-shaped conductor membrane are formed thereto in parallel to said resistor membrane so as to insulate both membranes. A rotary contact 7 made of a magnetic material moves while contacts with both fine wire membranes to connect the resistor membrane and the conductor membrane to obtain the resistance value corresponding to the position of the rotary contact 7. The rotary contact 7 is magnetically connected to the permanent magnet 9 present outside a square-shaped pipe 5 and fixed to a part of a doughnut-shaped float 8. Because the rotary contact 7 also moves as the float 8 falls corresponding to the position of a liquid level 10, the resistance value corresponding to the height of the liquid level can be outputted.

Description

DETAILED DESCRIPTION OF THE INVENTION Fuel gauges are used in automobiles, aircraft, and many other transport aircraft to measure the amount of fuel remaining in a fuel tank. The majority of these fuel meters are liquid level meters that measure the height of the fuel liquid in the tank.It also measures the amount of fuel such as petroleum or organic chemical synthesis liquid stored in storage tanks. Many level meters are used for this purpose, and the present invention provides a new method for the level meters currently in use.

An on-vehicle fuel gauge is widely used as one of the devices using the conventional technology. This involves floating a float in the fuel tank, and a contact point mechanically interlocked with the float moves on the winding resistance, creating a horizontal path where the output resistance value changes as the float height changes. ing. This fuel gauge has a poor resolution, ranging from a few percent to several tens of percent, due to the shape of the fuel tank not being proportional to the liquid level, poor resolution due to winding resistance, and other reasons. For other reasons, such as being controlled by a computer or due to the increasing demands of automobile users, fuel gauges with higher accuracy are required.

The liquid level meter of the present invention provides a new method of achieving a highly accurate fuel gauge with simple steps.

A level meter using the present invention as an on-vehicle fuel gauge will be described in detail below, but it is clear that the present invention can be used not only as an on-vehicle fuel gauge but also as a wide range of general liquid level meters.

A liquid level meter using a magnetic attraction force between a magnetic material fixed to a float shown in FIG. 1 and a magnetic contact point on a resistor for measuring the liquid level will be explained.

A connector 2 for taking out signals to the outside is fixed to the flange 1, and a lead terminal 3 from this connector is insulated from the flange and connected via a lead wire 12 to a resistance plate 6 for level measurement.

A thin line-shaped resistance film is formed on the surface of the resistance plate 6, and a thin line-shaped conductor film is formed parallel to this in a state where the two are not insulated. A rotating contact 7 made of a magnetic material moves while touching both wire films, connects the resistive film and the conductive film, and is configured to have a resistance value depending on the position of the rotating contact. 7 is magnetically connected to a magnetic body (permanent magnet) 9 fixed to a part of a donut-shaped float 8 located outside the rectangular tube 5. Therefore, when the float is lowered according to the position of the liquid level lO, the rotary contact also moves accordingly, making it possible to output a resistance value according to the height of the liquid level.

The second example shows an example in which this device is attached to an automobile fuel tank.
In the figure, 20 is this device, 21 is a fuel tank,
22 shows the fuel filler port.As is clear from the figure 0, the shape of the fuel tank is complicated, and there is no proportional relationship between the liquid level height h and the fuel gasoline volume. The figure shows one example of its characteristics, where the horizontal axis is the height from the bottom of the fuel tank to the liquid level, and the vertical axis is the height h, which shows the volume of gasoline.
When h is small, the volume rises slowly as shown in 31, but at the middle 1 m section it rises as shown in the curve 32, and as h increases, it again becomes a gentle curve as shown in 33. Therefore, there is no proportional relationship between the height h and the volume (2), resulting in a large error in the fuel gauge.

An object of the present invention is to provide a method for obtaining linearity between the level height and the capacity in a liquid level meter that obtains the fuel capacity from the liquid level height, and to provide a highly accurate device.

This will be further explained with reference to FIG. 4, which shows one example of the embodiment.

Resistance m-wires WA41-43 and conductor films 45-46 are formed on the surface of the resistance plate 6, and portions 47 and 48 are terminals for taking out the resistance output to the outside. One end of the resistive film and a part of the conductive film overlap at 44 and are connected. Since the rotating contact 7 shown in FIG. 1 rotates to connect the resistive films 41 to 43 and the conductive film 46, a constant resistance value of 47.48 is applied between the two terminals depending on the position of the rotating contact 7. is output to. The line width of this resistive film is wide at the lower part from the bottom, narrower at the center, and wider again at the upper part. Next, the details of the line width will be described. The height of the liquid level from the bottom of the fuel tank is X, the cross-sectional area of the container at that height is S (x), the volume of liquid when the container is 100% full is ■, and then The resistance value of the level meter is R1°.

Then, there is a case where the output resistance value R and the liquid volume V have a linear relationship.

On the other hand, if the thickness of the resistive film is t, the width is w(x), and the resistivity is the following, the following equation can be obtained together with the previous equation.

As shown by this equation, by selecting the line width of the resistive film that is inversely proportional to the cross-sectional area of the container, it is possible to accurately obtain a direct relationship between the capacitance FIt and the output resistance value R. This is shown in Figure 5. Various films can be used as resistive films.
As an example, a nickel-chromium film with a thickness of 6 units
R10°=100. Ω can be obtained.

In the description of this embodiment, a thin film has been described, but it is obvious that a metal foil can also be used. A pattern that changes the X-ray width according to 5(x) can be easily created by photoetching, or by masking or other means during film creation.

As described above, the present invention can correct errors caused by the shape of the fuel tank using a simple method, and is a very effective method technically and industrially.

[Brief explanation of drawings]

Fig. 1 shows an embodiment of the device according to the present invention, Fig. 2 shows an embodiment in which the device according to the invention is applied as a sensor for a vehicle fuel tank, and Fig. 4 shows an embodiment of the device according to the present invention. As an example, FIG. 5 is a diagram showing the characteristics of an embodiment of the device according to the present invention.

Claims (1)

[Claims] In a liquid level meter that uses magnetic attraction between a magnetic material fixed to a float and a magnetic contact point on a resistor for measuring the liquid level, the cross-sectional area of the resistive film wire at the internal height of the container is A liquid level meter characterized by a line width that is inversely proportional to .