JPH0749985B2 - Vehicle fuel gauge - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel gauge for a vehicle, which is provided in an automobile and displays a remaining fuel amount in a fuel tank.

(Prior Art) Generally, an automobile is equipped with a fuel gauge for displaying a remaining fuel amount in a fuel tank on a meter provided in a driver's seat. This fuel gauge includes, for example, as disclosed in Japanese Patent Laid-Open No. 57-211017, a float that is constrained on the liquid surface of a fuel in a fuel tank and moves up and down according to the change of the liquid surface, and this float. A liquid level detector that has a variable resistor whose resistance value changes according to the vertical movement of the liquid crystal and outputs an electric signal corresponding to the resistance value, and the position of the pointer is changed according to the signal from the liquid level detector. It is composed of a meter, etc. Then, when the fuel is in a so-called full state and the float is at the uppermost position, the pointer of the meter indicates the “F” (Full) position, and in accordance with the downward movement of the float due to the decrease in the fuel level, The pointer in the meter moves from the "F" position to the "E" (Empty) side due to the change of the resistance value or the change of the output signal in the liquid level detector.

By the way, it is customary to inject the fuel into the fuel tank until the tank is full, but the level of the liquid surface at the time of injecting the tank is not always constant. Also,
In the above-mentioned configuration, even if the liquid level at the time of full tank filling is always constant due to an error or variation in the mechanism that converts the position of the float into a resistance value or an output signal to the meter. , The pointer of the meter does not always indicate the “F” position.

Therefore, in the past, by restricting the upward movement of the float at the lower limit position of the variation range of the liquid level at the time of full tank or a position slightly lower than this position, the float becomes below the liquid surface at the time of full tank injection. It is set so as to be in a state of being slightly sunk, and the float is always positioned at a fixed upper limit position even if the liquid surface level varies. Further, with respect to the error in the mechanism for converting the position of the float into a resistance value or an electric signal, even if these errors occur in the direction of lowering the position of the pointer,
When the float is in the above upper limit position, adjust the output to the meter so that the pointer always indicates the "F" position (or a position slightly beyond that position), and the pointer has swung to the "F" side. It is set to be in a state.

As a result, when fuel is injected into the fuel tank to the full state, the above-mentioned guideline must always be "F" regardless of variations in the liquid level and errors in the mechanical and electrical system from the float to the guideline of the meter. "You will indicate the position.

(Problems to be solved by the invention) However, in the fuel gauge having the above-mentioned configuration, the float sinks below the liquid level when the tank is full, so if the liquid level does not drop to a certain extent, the float Does not move downwards, during which the meter pointer remains pointing to the "F" position despite the fuel being consumed. On the other hand, even if the regulation of the upper limit position of the float is abolished so that the float also moves down at the same time when the liquid level drops,
Since the pointer of the meter is swung to the “F” side, the float drops to some extent, and the resistance value or output signal of the liquid level detector changes more than a certain amount in the direction to move the pointer to the “E” side. Until then, the pointer is held in the state of pointing to the “F” position. As a result, when the fuel consumption from the full state is within a certain range, the pointer of the meter does not indicate the consumption correctly.

(Means for Solving Problems) The present invention addresses the above-described problems in the conventional fuel gauge, and relates to a mechanism for converting the dispersion of the liquid level and the position of the float into the amount of electricity when the fuel tank is full. Regardless of the error, the pointer always points to the “F” position when the tank is filled, and if the liquid level drops from this state, the pointer will immediately move from the “F” position to the “E” side. The present invention aims to display the fuel consumption correctly, and is characterized by having the following configuration for achieving this purpose.

That is, according to the present invention, the float is constrained on the liquid level in the fuel tank and moves up and down according to the change of the liquid level, and the resistance value changes according to the vertical position of the float, In a fuel gauge for a vehicle having a liquid level detector that outputs a corresponding signal to a display unit, a full tank sensor that detects a full tank state in which the liquid level in the fuel tank is a predetermined level or more,
The resistance value of the liquid level detector when the full tank sensor detects a full state is compared with a predetermined reference resistance value, and the output signal from the liquid level detector to the display unit is corrected according to the difference. And a correction means. The reference resistance value is set to such a value that the pointer on the display unit indicates the "F" position when the resistance value of the liquid level detector reaches this value. Further, in the present invention, there is no restriction on the upper limit position for the float, and the float is always positioned on the liquid surface.

(Operation) According to the above configuration, the position of the float or the resistance value of the liquid level detector corresponding to the position also varies with the variation of the liquid level when the fuel is fully filled into the fuel tank. However, when the full tank sensor detects a full tank state, the resistance value is compared with the reference resistance value corresponding to the "F" position of the pointer on the display unit, and the liquid level is detected by the correction value according to the difference. Since the output signal from the container to the display unit is corrected, a signal corresponding to the reference resistance value is always output during full tank injection, regardless of the actual resistance value. At the same time as the liquid level decreases, the position of the float or the resistance value of the liquid level detector also changes, and the output signal based on this resistance value is similarly corrected by the correction value. Changes from the value corresponding to the reference resistance value when the tank is full, depending on the drop in the liquid level or the float. Therefore, the pointer on the display unit always indicates the “F” position at the time of full tank filling, and immediately moves to the “E” side as the liquid level decreases.

(Example) Hereinafter, the Example of this invention is described based on drawing.

As shown in FIG. 1, a fuel tank 1 has an inlet 2 for injecting fuel into the tank 1, and a fuel supply pipe 3 for supplying fuel from the tank 1 to an engine (not shown). And a liquid level detection unit 4 constituting the fuel gauge is provided in the tank 1. The unit 4 is composed of a variable resistor 6 housed in a case 5 mounted inside the upper surface of the tank 1, and a float 7 held on the liquid surface of the fuel in the tank 1. The movable contact 6a of the resistor 6 and the arm 8 to which the float 7 is attached at the tip are connected, and they are configured to integrally swing about a fulcrum provided on the case 5. . Then, when the float 7 which is always restrained on the liquid surface of the fuel in the tank 1 moves up and down with the displacement of the liquid surface, the movable contact 6a of the variable resistor 6 is spirally formed via the arm 8. Sliding on the resistance wire 6b, the resistance value r of the resistor 6 changes according to the liquid level or the vertical position of the float 7. Then, the liquid level signal S ₁ corresponding to this resistance value r is output from the liquid level detection unit 4.

On the other hand, outside the fuel tank 1, a controller 10 to which the liquid level signal S ₁ is input is provided. The controller 10 is configured to operate when the ignition switch 11 is turned on, send an output signal S ₂ corresponding to the liquid level signal S ₁ to the meter 12, and move the pointer 12a in the meter 12.

However, in addition to the liquid level signal S ₁ , the controller 10 receives a signal S ₃ from the full tank sensor 13 attached to the fuel tank 1. This full tank sensor 13 is attached at a position in the fuel tank 1 corresponding to a predetermined liquid level L ₀ , and when the liquid level is above the level L _0, it comes into contact with the fuel, so that the liquid level becomes the level L _0. It is detected that the above is the full tank state, that is, the full tank signal S ₃
Is sent to the controller 10. When the controller 10 receives the full signal S ₃ , the controller 10 sets the resistance value r of the variable resistor 6 indicated by the liquid level signal S ₁ from the liquid level detection unit 4 and the preset reference resistance value r _0.
And the difference Δr (= r−r ₀ ) is set as a correction value, and the output signal to the meter 12 is set by using this value Δr.
It is designed to correct S ₂ .

Here, with respect to the liquid level L, that is, the position of the float 7, the resistance value r of the variable resistor 6 in the liquid level detection unit 4 has a characteristic as shown in FIG. 2, for example. , The liquid level L is the full tank level L ₀
At this time, the resistance value r is set to be equal to the reference resistance value r ₀ , and at this time, the output signal S ₂ is set to position the pointer 12a of the meter 12 at the “F” position.

Next, the operation of the above embodiment will be described with reference to the flowchart of FIG. 3 showing the operation of the controller 10.

First, when the ignition switch 11 is turned on to start the engine of the car, the controller 10
Is whether or not the inside of the fuel tank 1 is in a full state based on the signal S ₃ from the full tank sensor 13 in step P ₁ of the flowchart, that is, whether the liquid level L is equal to or higher than a predetermined full tank level L _0. To determine. Then, when the fuel tank 1 is full, for example immediately after fuel injection, the controller 10 then changes according to the signal S ₁ from the liquid level detection unit 4 according to steps P ₂ and P _2. inputs the resistance value r ₁ of the resistor 6 is compared with the reference resistance value r ₀ in advance is set as the resistance value r _1, calculates the difference _{Δr (= r 1 -r 0)} ,
Then, the controller 10 inputs the resistance value r ₂ of the liquid level detection unit 4 again according to the steps P ₄ and P ₅ and sets the resistance value r ₂ to the correction value Δr. Correct using
The output value R (= r ₂ −Δr) is calculated. By the way, in this case, inputting the resistance value r _{2 in} step P ₄
Immediately after the resistance value r ₁ is input by P ₂ and the liquid level L has hardly changed, r ₁ = r ₂ and therefore the output value R is R = r ₂ −Δr = r ₁ − (R ₁ −r ₀ ) = r ₀ , which is corrected to the reference resistance value r ₀ . Since this reference resistance value r ₀ corresponds to the “F” position of the pointer 12a in the meter 12, the liquid level does not match the predetermined full tank level L ₀ due to the dispersion at the time of full tank injection. also, by corrected output value R to the reference resistance value r _0, pointer 12a of the meter 12 is to instruct the "F" position.

Then, when the fuel in the fuel tank 1 is consumed from the full tank state and the float 7 gradually moves downward due to the decrease in the liquid level, the resistance value r of the liquid level detecting unit 6 also gradually changes ( Decrease. On the other hand, the controller 10 repeatedly inputs the resistance value r (r ₂ ) by repeatedly executing the above steps P ₄ and P _5, and at the same time, corrects the resistance value r ₂ set in the above step P ₃ Value Δ
Correction is performed using r, and the corrected value (r ₂ −Δr) is output to the meter 12 as the output value R. Therefore, this output value R changes from the value r ₀ at the time of full tank according to the change of the actual resistance value r, and as a result, the pointer in the meter 12 responds to the decrease of the liquid level L by "F". It will move from the "position" to the "E" side immediately.

That is, assuming that the liquid level L at the time of full tank injection is, for example, the level L '(> L ₀ ), as indicated by the symbol a in FIG. 2, if the above correction is not performed, the meter 12
Since the pointer 12a of the above is in a state of being completely swung to the “F” side, and the resistance value r changes to the reference resistance value r ₀ (the liquid level is
L ₀ before decrease) is made to be held in the pointer 12a is "F" position, the liquid level L 'by the correction
The output value R at the time of is set to the reference resistance value r _0, and the code b
As shown in, the output value R also changes from this value as the liquid level L decreases, and as a result, the pointer 12a of the meter 12 becomes "F".
It will move from the position to the "F" side immediately.

The controller 10 turns off the ignition switch 11.
Operation stops the operation and the next ON operation steps
The operation starts again from P _1, but if the fuel tank 1 becomes full at the start of the operation, steps P ₄ and P ₅ are immediately executed from step P ₁ . In this case, step P ₅
As the correction value Δr used in step ₃ , the correction value set at the previous execution of step P ₃ is used.

In addition, in the conventional fuel gauge, when the tank is full, the pointer of the meter indicates a position slightly beyond the “F” position, but according to the present plan, there is no need to shift the indication in this way. Alternatively, the "F" position may be correctly indicated when the tank is full.

(Effects of the Invention) As described above, according to the vehicle fuel gauge of the present invention, the pointer of the meter always indicates the "F" position when the fuel tank is filled with the fuel, and the fuel consumption is accompanied by the fuel consumption. If the liquid level in the tank drops, the pointer will immediately move from the “F” position to the “E” side. This eliminates the problem that the pointer is held in the “F” position until a certain amount of fuel is consumed as in the past, and the meter pointer always indicates the fuel consumption amount or the remaining fuel amount in the tank. Will be instructed.

[Brief description of drawings]

The drawings show an embodiment of the present invention. FIG. 1 is a system diagram showing the overall configuration of a fuel gauge, FIG. 2 is a characteristic diagram showing the output characteristics of a controller, and FIG. 3 is a flowchart showing the operation of the controller. It is a figure. 1 ... Fuel tank, 6 ... Liquid level detector (variable resistor), 7 ...
Float, 10 ... Correction means (controller), 12 ... Display unit (meter), 13 ... Full sensor.

Claims (1)

[Claims] 1. A fuel gauge for a vehicle for displaying the remaining amount of fuel in a fuel tank, comprising a full tank sensor provided in the fuel tank for detecting a full tank state in which a liquid level of fuel is a predetermined level or more. , A float that is constrained on the liquid surface and moves up and down according to a change in the liquid surface, and a resistance value is changed according to the vertical position of the float, and a signal corresponding to the resistance value is output to the display unit. The liquid level detector and the liquid level detector when the full tank sensor detects a full state are compared with a predetermined reference resistance value, and the output signal to the display unit is corrected according to the difference. A fuel gauge for a vehicle, comprising: a correcting means.