JP2533937B2 - Fuel gauge with remaining amount warning device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Industrial field of application) The present invention indicates the remaining amount of fuel, and also issues a warning when the remaining amount of fuel falls below a predetermined amount. The present invention relates to a fuel gauge with a warning device.

(Prior Art) As a fuel gauge with a remaining amount warning device, which indicates the remaining fuel amount and is equipped with a warning lamp that lights up when the remaining fuel amount falls below a predetermined amount, for example, one shown in FIG. 12 is used. Are known. According to this fuel gauge, a scale 110 displaying the remaining amount of fuel on the dial 100, a pointer 120 moving on the scale 110,
Warning lamp that lights up when the remaining fuel amount falls below a specified amount
It is equipped with 130 and. In FIG. 12, 160 is a switch and 170 is a power source.

Here, the coils L _{1 to} L ₃ (see FIG. 13) for moving the pointer 120 and the warning lamp 130 are connected to the sender 150 equipped in the fuel tank 140. This sender 150 is, for example, the 14th
As shown in the figure, a disc-shaped mounting board 151 fixed to the fuel tank 140, a stay 153 mounted on the frame 152 of the mounting board 151, and a tip portion (lower end portion in the drawing) of the stay 153 are provided. Attached thermistor for fuel level detection
154, a float 156 provided with a float 155 at the tip (lower end in the drawing) and a base end (upper end in the drawing) rotatably attached to the frame 152, and fixed to the base end side of the float arm 156. And a resistance plate 159 which is fitted and fixed to the frame 152 and which comes into sliding contact with the slider 158 as the float arm 156 slides.

Note that FIG. 15 shows the resistance plate 159, a substrate 159a made of ceramic or the like, a plurality of resistors 159b formed by printing on the substrate 159a, and also formed by printing on the substrate 159a, one end of which is a resistor. It is composed of a plurality of conductive contact bodies 159c connected to the body 159b and having the other end slidably contacting the slider 158. Further, one end of the resistor 159b is connected to the coils L _{1 to} L ₃ that move the pointer 120, and the thermistor 154 causes the warning lamp 1 to operate.
It is connected to 30 (see Figure 13).

According to the fuel gauge with the remaining amount warning device, when the remaining fuel amount decreases and the liquid level drops, the float 155 descends accordingly,
The float arm 156 slides. This float arm 156
The sliding member 158 causes the resistor 159b (conductive contact member 159
c) The resistance changes by sliding on the coil, and the change in the resistance changes the current flowing through the coils L _{1 to} L ₃ . Due to this change in current, the combined magnetic field formed by the coils L _{1 to} L ₃ changes, and the pointer 120 moves on the scale 110 to indicate the remaining fuel amount.

Further, when the remaining fuel amount decreases to a predetermined amount or less, that is, when the liquid level drops to the installation position of the thermistor 154, the thermistor 154 is exposed to the air from the state of being immersed in the fuel.
As a result, the resistance value of the thermistor 154 changes due to the temperature change of the thermistor 154, and the warning lamp 130 lights up.

(Problems to be Solved by the Invention) In the fuel gauge with the remaining amount warning device, the resistance change of the thermistor 154 when the thermistor 154 is exposed from the fuel to the air is used to control the current flowing through the warning lamp 130. Therefore, there is a problem that the operating range of voltage and temperature is narrow,
In addition, the influence of the load characteristics is extremely large, and there is a problem that the local resistance and the warning lamp 130 are limited.

Also, the part related to the indication of the remaining fuel amount (float arm
156, the slider 158, the resistance plate 159, etc.) and the portion related to the fuel level warning (stay 153, thermistor 154, etc.) operate completely differently, so that the fuel will be exhausted to the extent that a warning is already issued by the level command. The warning lamp 130 does not light even if it is decreasing, or the warning lamp 130 is lighting even though the fuel is not decreasing until the warning is issued by the remaining amount instruction. There was a problem that the warning did not work well.

Further, since the thermistor 154 is installed near the bottom surface of the fuel tank 140 so as to issue a warning when the remaining fuel level is low, the stay 153 becomes long, and the stay 150 is attached when the sender 150 is attached to the fuel tank 140. 153 and Float Arm 15
There was also a problem that we had to be careful not to get entangled with 6.

This invention solves the above-mentioned problems of the prior art,
The purpose is that the voltage and temperature can be used in a wide range, load resistance and warning lamps are not specified, and the remaining amount indication and the remaining amount alarm are accurately linked. It is an object of the present invention to provide a fuel gauge with a remaining amount warning device that does not require special care when mounted on a fuel gauge.

[Structure of Invention]

(Means for Solving the Problem) In order to achieve the above object, in the fuel gauge with the remaining amount warning device according to claim (1) of the present invention, the resistance plate and the resistance plate on the resistance plate in accordance with the liquid level displacement in the fuel tank. Equipped with a resistor consisting of a slider that slides a resistor, configured to indicate the remaining fuel amount by the resistance change of this resistor, and warn when the remaining fuel amount falls below a predetermined amount In a fuel gauge with a remaining amount warning device equipped with a warning unit that emits a warning, a remaining amount warning point is provided on the resistor on the resistance plate, and the resistor and the warning unit are connected by a circuit, and the slider has a resistance. When the remaining amount warning point of the body is reached, the warning means is operated.

The fuel gauge with the remaining amount warning device according to claim (2) is characterized in that a delay circuit is provided in the circuit according to claim (1).

Further, in the fuel gauge with the remaining amount warning device according to claim (3),
The delay circuit according to claim (2) is incorporated in a circuit of a resistor, mounted on a substrate of a resistance plate, and sealed with a sealing material having durability against fuel.

Furthermore, the fuel gauge with the remaining amount warning device according to claim (4) is characterized in that the delay circuit according to claim (2) is provided with control means for controlling charging and discharging of the capacitor by voltage.

In the present invention, the "remaining amount warning position" refers to the sliding position of the slider on the resistor when the remaining fuel amount decreases until a warning is issued.

A warning lamp, a buzzer, or the like is used as the "warning means".

(Operation) In the fuel meter with the remaining amount warning device according to claim (1), the slider slides on the resistor in accordance with the displacement of the liquid level of the fuel, and the resistance of the resistor corresponds to the remaining amount of fuel. Change. Due to this resistance change of the resistor, for example, the current flowing through the coil that drives the pointer changes, and due to this change of the current, the combined magnetic field of the coil changes, and the pointer indicates the remaining fuel amount. When the amount of remaining fuel decreases and the slider slides to the remaining amount warning point on the resistor, the circuit causes a current to flow through the warning means, and the warning means operates.

Further, in the fuel gauge with the remaining amount warning device according to claims (2) and (3), the warning means does not operate immediately even when the slider moves to the remaining amount warning position, and the delay circuit causes a delay for a certain time. Operate.

Furthermore, in the fuel gauge with the remaining amount warning device according to claim (4), the charging / discharging of the delay circuit is controlled by the control means that operates in response to the voltage change caused by the presence or absence of the current flowing at the remaining amount warning point. The warning means does not operate undesirably even if a small amount of current flows due to the insulation of the resistance plate being lowered.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is an electric circuit diagram of a fuel gauge with a remaining amount warning device according to the present invention. In the figure, reference numeral 10 is a resistor mounted on a sender (not shown), L _{1 to} L ₃ are coils for driving a pointer (not shown), 20 is a warning lamp, 30 is a switch, and 40 is a power supply.

The resistor 10 includes a slider 11 fixed to the base end side of a float arm of a sender (not shown) and a resistance plate 12 also fixed to a frame of a mounting board of the sender (not shown). The slider 11 moves with the resistance plate 12
The resistance is changed by sliding on the resistor 12b (conductive contact 12c).

Here, as shown in FIG. 2, the resistance plate 12 includes a plurality of resistance bodies 12b and a plurality of resistance bodies 12b at one end on a substrate 12a such as ceramics.
A plurality of conductive contact bodies 12c, which are connected to 12b and on which the slider 11 slides at the other end, are formed by printing. Then, one end (A end shown in FIG. 1) of the resistor 12b is connected to the coil L ₁
Is connected between the L _2, also resistors slider 11 slides
The other end of 12b is connected to the ground G via the conductive contact 12c and the slider 11.

When the fuel tank (not shown) is filled with fuel, the slider 11 is located on the F side in FIG. 1, and slides toward the E side in FIG. The resistance value of the resistor 12b changes as the armature 11 slides from the F side to the E side.

Figure 3 shows the displacement of the fuel level (change in the remaining amount) and the resistance plate 12.
In the graph which shows the relation with the voltage between A and B of (resistor 12b),
As is clear from the graph, the liquid level is high (slider
The voltage is low in the state where 11 is located on the F side), and as the liquid surface descends from this state, the slider 11 slides to the E side and the voltage rises.

In this way, the slider 11 slides from the F side to the E side of the resistor 12b due to the displacement of the fuel liquid level, and the resistance value of the resistor 12b changes (the voltage between A and B changes). by), the magnetic field generated in the coil L ₁ ~L ₃ is changed in value of the current flowing through the coil L ₁ ~L ₃ is changed, the fuel guidance this change in the magnetic field to move the on the scale (not shown) Indicate the remaining amount.

The present invention is characterized in that the above-mentioned portion for indicating the remaining fuel amount is used to operate the means for warning that the remaining fuel amount is low. Not using a thermistor.

That is, the sliding position on the resistor 12b (conductive contact body 12c) of the slider 11 when indicating the fuel remaining amount reduced to the extent that refueling is required is the remaining amount warning point 13, and A circuit 50 is provided between the quantity warning point 13 and the warning lamp 20 to connect them. In addition, a diode 14 is interposed between the remaining amount warning point 13 and the F-side resistor 12b, and the anode side of the diode 14 is connected to the resistor 12b on the F side of the remaining amount warning point 13 and the cathode. Side to the remaining amount warning point 13
When 11 is located on the F side of the remaining amount warning point 13, the circuit
Current is prevented from flowing to the warning lamp 20 via 50.

The diode 14 is connected to the substrate 12 as shown in FIG.
Although it is mounted on a, if it is arranged between the remaining amount warning point 13 and the resistor 12b on the F side in a circuit,
It may be provided on the warning lamp 20 side. A buzzer or the like may be used instead of the warning lamp 20.

In this way, the warning lamp 20 can be turned on even when the thermistor is not used, when the remaining fuel amount has decreased to the point where refueling is necessary. That is, when the remaining fuel amount decreases and the slider 11 reaches the position of the conductive contact body 12c corresponding to the remaining amount warning point 13, the slider 11, the conductive contact body 12c,
A current flows through the warning lamp 20 through the circuit 50 and the resistor R ₆ , and the warning lamp 20 is lit. Sliding element
Even 11 is moved to the E side, the warning lamp 20 slider 11, electrically conductive contact member 12c, the resistor 12b, since the current flows through the circuit 50, the resistor R _6, remains lit.

Even current flows through the coil L ₁ ~L ₃ while the slider 11 is moved from the low warning point 13 on the E side, performs the remaining amount indication.

FIG. 4 shows a modification of the above embodiment, in which the slider 11
Is connected to the + side of the power supply 40 via the switch 30, the anode side of the diode 14 is connected to the remaining amount warning point 13, and the cathode side is connected to the resistor 12b on the F side of the remaining amount warning point 13. are doing. That is, plus and minus are opposite to the circuit shown in FIG. The other points are the same as those of the circuit shown in FIG.

Also in this case, as in the circuit shown in FIG.
When reaches the remaining amount warning point 13, current flows through the warning lamp 20 and the lamp lights.

In the circuit of the embodiment shown in FIGS. 1 and 4 above,
The current that turns on the warning lamp 20 is the slider 11, conductive contact.
Although it passes through 12c, the remaining amount warning point 13, the circuit 50, and the resistor R ₆ , if this current value is large, there is a problem that the remaining amount instruction is adversely affected after the remaining amount warning point 13. Further, the float arm (not shown) vibrates due to the displacement of the liquid level of the fuel in the fuel tank due to vibration, etc.
If you move to the F side from 13, there is a problem that the warning lamp 20 repeatedly turns on and off and flickers.

FIG. 5 shows another embodiment in which a delay circuit 60 is interposed in the circuit 50 in order to solve such a problem. Sixth
The figure specifically shows the delay circuit 60 of FIG.

The delay circuit 60 is composed of, for example, transistors Q ₁ , Q ₂ , Q ₃ , diodes D ₁ , D ₂ , resistors R _{1 to} R _5, and a capacitor C. Here, the base of the transistor Q ₁ is connected to the remaining amount warning position 13 via the resistor R ₁ . Also,
The transistors Q ₂ and Q ₃ are connected in Darlington, and their collectors are connected to the warning lamp 20 via the resistor R ₆ . Further, the diodes D _1, D _2, resistors R ₁ to R _5, the capacitor C is interposed between the base of the collector of the transistor Q ₂ of the transistor Q _1. The resistance value of the resistor R ₁ is
The current is set to be larger than the resistance R ₇ connected to the resistance plate 12b and the coil L ₁ and the current flowing through the coils L _{1 to} L ₃ even if the slider 11 moves from the remaining amount warning point 13 to the E side. I try not to affect.

In this embodiment, when the slider 11 moves to the remaining amount warning point 13, the transistor Q ₁ becomes conductive, and after a time delay determined by the time constant R ₃ · C by the resistor R ₃ and the capacitor C,
The transistors Q ₂ and Q ₃ become conductive, and the warning lamp 20 lights up.

The float arm (not shown) swings due to the displacement of the liquid level of the fuel in the fuel tank due to vibration, etc.
Is temporarily moved to the F side of the remaining amount warning point 13, the transistor Q ₁ is temporarily turned off, and the capacitor C is instantaneously discharged via the diode D ₂ resistor R ₂ at this time. The flicker of the warning lamp 20 does not occur. Further, even when the slider 11 is moving from the remaining amount warning position 13 toward the E side, there is no influence on the remaining amount instruction. Further, since the transistors Q ₂ and Q ₃ are connected in Darlington to amplify the current, the size and form of the warning means as a load are not limited, and various warning means other than the warning lamp 20 can be used.

FIG. 7 shows still another embodiment in which the delay circuit 60 is incorporated in the circuit of the resistor 12b. FIG. 8 specifically shows the delay circuit portion of FIG. The configuration of the delay circuit 60 is the same as that shown in FIG. 5, and the resistance values of the resistors R _{1 to} R ₃ etc. in the delay circuit 60 are those connected to the resistor 12b and the coil L ₁ . It is set larger than R ₇ .

When the delay circuit 60 is incorporated in the circuit of the resistor 12b as in this embodiment, the voltage between A and B of the resistor 12b causes the remaining amount warning point 13
Since it is large in the vicinity (see FIG. 3), it is not necessary to provide a power source dedicated to the delay circuit 60.

When the power supply dedicated to the delay circuit 60 is provided, there is more freedom in designing the circuit than in this embodiment.

FIG. 9 is a perspective view showing the appearance of the resistance plate 12 in the embodiment of FIG. 7, in which the delay circuit 60 and the diode 14 are mounted on the substrate 12a, and the sealing material 70 is durable against fuel. It is sealed by. Therefore, a dedicated board for mounting the delay circuit 60 is not required, and the board 12a of the resistance plate 12 can be effectively used.

FIG. 10 shows still another embodiment, which is the fifth embodiment.
The configuration is the same as that of the other embodiments shown in the figure, but only the delay circuit is different, and thus the other parts are denoted by the same reference numerals and detailed description thereof is omitted. This embodiment includes transistors Q ₁ , Q ₂ and Q ₃ as in the embodiment of FIG.
The big difference is that the Sienna diode ZDI is inserted between the remaining amount warning point 13 and the transistor Q ₁ .
Now, when the slider is on the F side of the remaining amount warning point 13, the potential on the cathode side of the Zener diode ZDI is high, so the transistor Q ₁ is in the ON (operating) state and the capacitor is charged. Therefore, since the transistors Q ₂ and Q ₃ are in the OFF state, no current flows through the warning lamp 20. When the slider 11 reaches the remaining amount warning point 13, the potential on the cathode side of the Zener diode ZDI becomes low, so the transistor Q ₁ turns off.
Then, the capacitor C is charged. Then, the transistors Q ₂ and Q ₃ are turned on after a delay of the time determined by the time constant of R ₁₄ · C,
A current flows through the warning lamp 20 and it lights up. As described above, in this embodiment, the Zener diode ZDI and the transistor Q ₁ constitute the control means 70 for the capacitor C, which corresponds to the voltage that changes depending on the presence or absence of the current passing through the remaining amount warning point. The operation controls the charging and discharging of the capacitor C.

FIG. 11 shows a modification of the another embodiment shown in FIG. 10, in which the control means 70 is different from the other embodiment in that the comparator IC
The difference is that it is composed of. As shown in FIG. 11, the midpoint between the resistor pair R ₂₁ and R _{22 and} the midpoint between the resistors R ₂₃ and R ₂₄ are inputs to the comparator IC, respectively. When the slider 11 is on the F side of the remaining amount warning point 13, the potential at the intermediate point between the resistors R ₂₁ and R ₂₂ is higher than that at the intermediate point between the resistors R ₂₃ and R ₂₄ , so the comparator IC turns on. However, the capacitor C is not charged, and the transistors Q ₂ and Q ₃ are in the OFF state. Slider 11
When reaches the remaining amount warning point 13, on the contrary, the potential at the intermediate point between the resistors R ₂₁ and R ₂₂ becomes lower, so the comparator IC turns off.
Then, the capacitor C is charged, delayed by the time constant determined by the capacitor C and the resistor R _28, and the transistor Q ₂ Q ₃
Turns on and the warning lamp 20 lights up.

A device for controlling the charging and discharging of the capacitor C by the change of the voltage as in this embodiment is not effective even when the resistor 12b is dipped in a low insulating material such as alcohol and a slight current flows. There is no possibility that the capacitor C is charged as desired and the warning lamp 20 is turned on.

〔The invention's effect〕

As described above, according to the invention of claim (1), the means for warning that the remaining fuel amount is low is operated using the portion (resistor) for indicating the remaining fuel amount. Since a thermistor is not used as in the past, the voltage and temperature can be used in a wide range and the load resistance and warning lamp are not specified. In addition, since the stay for indicating the thermistor can be omitted, it is not necessary to take special care when mounting the sender on the fuel tank.

Further, according to the invention of claim (2), since the delay circuit is provided, there is no flicker problem of the warning lamp, and the circuit of the portion for indicating the remaining amount is not adversely affected.

Further, according to the invention of claim (3), since the delay circuit is incorporated in the low antibody and mounted on the resistor plate, a power source or a substrate dedicated to the delay circuit is not required, and the substrate of the resistor plate can be effectively utilized. Can be planned.

Further, according to the invention of claim (4), since the charging / discharging of the capacitor is controlled by the change of the voltage, even if a small current flows through the resistance plate due to the insulation decrease of the resistor,
As a result, the capacitor is not charged and the warning lamp does not light up.

[Brief description of drawings]

1 to 4 show an embodiment of the present invention.
FIG. 1 is an electric circuit diagram, FIG. 2 is a perspective view of a resistance plate, and FIG. 3 is a liquid level displacement of fuel (change in remaining amount) and a resistance plate 12 (resistor 12).
Fig. 4 is a graph showing the relationship between the voltage between A and B in b).
FIG. 5 is a modification of the circuit shown in FIG. 5, FIGS. 5 and 6 are circuit diagrams showing other embodiments, and FIGS. 7 to 9 show still another embodiment. 7 is a circuit diagram, 8
7 is a circuit diagram specifically showing the delay circuit portion of FIG. 7, FIG. 9 is a perspective view showing the appearance of the resistance plate of FIG. 7, and FIGS. 10 and 11 are further different views. Fig. 10 shows an embodiment, Fig. 10 is a circuit diagram, and Fig. 11 is a circuit diagram of a modified example.
Further, FIGS. 12 to 15 show the prior art, FIG. 12 is a schematic explanatory view showing the entire apparatus, FIG. 13 is a circuit diagram, FIG. 14 is a perspective view showing the appearance of the sender, and FIG. FIG. 3 is a perspective view showing the appearance of a resistance plate. C …… Capacitor 10 …… Resistor 11 …… Slider 12 …… Resistor plate 12a …… Board 12b …… Resistor 12c …… Conductive contact body 13 …… Remaining amount warning point 14 …… Diode 20 …… Warning means (warning lamp) 50 …… Circuit 60 …… Delay circuit 70 …… Control means

Claims (4)

(57) [Claims] 1. A resistor comprising a resistance plate and a slider that slides a resistor on the resistance plate in accordance with the displacement of the liquid level in the fuel tank, the fuel remaining by the resistance change of the resistor. In a fuel gauge with a fuel level warning device, which is configured to give a fuel quantity instruction and is equipped with warning means for issuing a warning when the fuel remaining amount falls below a predetermined amount, a fuel level warning point is provided on the resistor on the resistance plate. And the resistor and the warning means are connected by a circuit, and when the slider reaches the remaining quantity warning point of the resistor, the warning means is operated. Fuel gauge with device. 2. A fuel gauge with a remaining amount warning device according to claim 1, wherein said circuit is provided with a delay circuit. 3. The delay circuit is incorporated in a circuit of a resistor, mounted on a substrate of a resistance plate, and sealed with a sealing material having durability against fuel (2). Fuel gauge with the indicated remaining amount warning device. 4. The delay circuit delays the operation of the warning means, and the charging / discharging of the capacitor is controlled by a control means which operates in response to a voltage change caused by the presence / absence of a current flowing through the remaining amount warning point. The fuel gauge with the remaining amount warning device according to claim 2, wherein