JPH0434427Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Field of Application) The present invention relates to a fuel gauge for a vehicle, and particularly to a fuel gauge for a vehicle equipped with a two-compartment fuel tank.

(Prior art) Conventionally, when a fuel tank of an automobile is placed, for example, directly above the drive shaft, a so-called two-chamber separated type fuel tank is used, in which the bottom surface of the fuel tank is raised upward and the fuel storage chamber is separated into left and right sides. may be used. In such a fuel tank, the liquid levels in both chambers (first chamber and second chamber) tend to become imbalanced when the vehicle turns or tilts. Therefore, when the liquid level in the first chamber that is suctioned to the fuel supply pipe drops significantly, the fuel is transferred from the second chamber side via the communication pipe using the transfer pump to maintain the liquid level in the left and right chambers. Generally, a configuration is adopted in which the total amount of fuel in both the left and right chambers is displayed on the fuel meter. (For example, see JP-A-60-94819).

(Problem to be solved by the invention) However, the capacities of the left and right chambers of the fuel tank as described above are not necessarily constant, and if further movement of fuel occurs during the transfer operation of the fuel transfer pump, the above-mentioned problems generally occur. Since the amount of movement is larger than the transfer capacity of the transfer pump, there is a problem in that sudden changes in the liquid level occur and the readings on the fuel meter (especially in the case of a pointer type) fluctuate greatly.

(Means for solving the problem) The present invention was made with the aim of solving the above problem, and includes a first chamber on the suction side connected to the fuel supply pipe, and a first chamber separated from this. A two-chamber separated type fuel for an automobile, in which second chambers having different capacities are communicated with each other by a communicating pipe, and a fuel transfer pump is interposed in the communicating pipe to send fuel from the second chamber to the first chamber. A tank, a liquid level detection means provided in each of the first chamber and the second chamber, an addition means for receiving the outputs of these two liquid level detection means and adding the two outputs, and an output of the addition means. and a drive motor that drives the fuel transfer pump when the liquid level detected by the liquid level detection means on the first chamber side falls below a predetermined value. In a vehicle fuel gauge comprising:
a fuel transfer pump drive motor operation detection means for detecting the operation of the fuel transfer pump drive motor; and a liquid level display means when the fuel transfer pump drive motor operation detection means detects the operation of the fuel transfer pump drive motor. display value control means for prohibiting the operation of changing the display value, and the fuel transfer pump drive motor operation detection means and the display value control means are turned on and off in conjunction with mutually opposite states.
It is characterized by being constructed with two sets of interlocking contacts.

(Function) Therefore, according to the above means, when the fuel transfer pump is operated while the fuel transfer pump drive motor is operating, the display value of the liquid level display means is always prohibited from changing, and is fixed to the previous display value. Therefore, even if fuel moves from the first chamber to the second chamber or from the second chamber to the first chamber due to turning of the vehicle when the fuel transfer pump operates, the displayed value of the liquid level will not change. will no longer fluctuate.

Furthermore, in the case of a configuration based on a pointer-type meter as described above, it is sufficient to simply cut off the power to the liquid level display means in response to the operation of the fuel transfer pump drive motor, and the holding means such as memory is required Not needed at all.

Therefore, the fuel transfer pump drive motor operation detection means and display value control means for realizing the above-mentioned function should also be configured extremely simply and at a low cost by only using ON and OFF contacts that operate in reverse in conjunction with each other. I can do it.

(Example) Hereinafter, an example of the present invention will be described in detail based on the drawings.

First, in Fig. 1, the symbol FT indicates a fuel tank device of an automobile.
The FT includes a two-chamber separated fuel tank 1, float sensors 2A and 2B located in the left and right two chambers 7A and 7B in the fuel tank 1, a receiver side control unit 3, and a fuel display meter 4. A first chamber 7A on the suction side and a second chamber 7B adjacent thereto are formed in the fuel tank 1 and communicated with a fuel supply pipe 6 for supplying fuel to the engine. The upper parts of both chambers 7A and 7B communicate with each other, while the lower parts are separated from each other by a semi-cylindrical bulge 8 through which the main drive shaft of the automobile passes.

Also, when the fuel is biased toward the second chamber 7B,
From the second chamber 7B side to the first chamber 7A on the suction side
A communication pipe 9 is attached to communicate the lower part of the second chamber 7B and the first chamber 7A, and this communication pipe 9 has a connection pipe 9 from the second chamber 7B side to the first chamber 7A side. A fuel transfer pump 10 is interposed to transfer fuel to the engine, and a driving motor 10a of this fuel transfer pump 10 is connected to the power source 5 via a relay switch 11 as shown in FIG.

Each of the float sensor 2A for detecting the liquid level on the first chamber 7A side on the suction side and the float sensor 2B for detecting the liquid level on the second chamber 7B side is as shown in detail in FIG. , float arm 13A is attached to floats 12A and 12B,
One end of the float arms 13B is hinged, and the other ends of the float arms 13A, 13B are further hinged to the brackets 16A, 16B of the metal mounting plate 17.
Brushes 14A, 14B are fixed to the other end of B, and the tips of the brushes 14A, 14B are slidably contacted with the surfaces of resistors 15A, 15B provided on the mounting plate 17 in a conductive manner. There is. The upper ends of the resistors 15A and 15B are connected to the mounting plate 17.
The brushes 14A, 14B are grounded to the fuel tank 1 through the base plate 18, and are connected to the control unit 3 by conductive wires (not shown) from the upper ends of the brushes 14A, 14B. In this way, when the floats 12A, 12B are lowered as the liquid level in each of the chambers 7A, 7B is lowered, the float arms 13A, 13B swing downward, and in conjunction with this, the brush 14
A, 14B swings upward, and the resistors 15A,
The resistance values of variable resistors (potentiometers) 15a and 15b consisting of brushes 15B and brushes 14A and 14B decrease.

Next, the configuration of the receiver-side control unit 3 will be explained in detail with reference to FIG.

The control unit 3 is roughly comprised of an addition circuit 20, a meter drive circuit 30, a discrimination circuit 40, a fuel transfer pump motor drive circuit 50, and a display value control circuit 60.

First, set the power supply voltage (12V) of the battery power supply 5 above.
Constant current sources 21a, 21b and current limiting resistors 22a, 22b are connected to the output line 19E of the constant voltage circuit 19, which is a voltage regulator that lowers the voltage to 7V using a DC/DC converter, to the variable resistors 15a, 15b. are connected in series, and each of the variable resistors 15a,
A constant current flows through 15b. Then, due to the drop in the liquid level, each of the variable resistors 15a, 15
As the resistance value of b decreases, points A and B in the circuit leading to each of the variable resistors 15a and 15b decrease.
The voltage at the point also gradually decreases from a predetermined value.

The adding circuit 20 adds the amount of fuel in the first chamber 7A on the suction side in the fuel tank 1 and the amount of fuel in the second chamber 7B, and sends the total amount to the fuel display meter 4 via the meter drive circuit 30. This adder circuit 20 connects each of the two reference voltage setting resistors 24a, 24b connected in parallel to the output line 19E of the constant voltage circuit 19 to the "-" of the operational amplifiers 25a, 25b. " side terminal (reference side) is connected, and the output side terminal of each of these operational amplifiers 25a, 25b is connected to the base of each PNP transistor 23a, 23b, while each of these PNP transistors 23
The emitters of a and 23b are connected to the "-" side terminals of the operational amplifiers 25a and 25b, and the collectors of the PNP transistors 23a and 23b are commonly connected to form a meter drive circuit 30.
It is adapted to supply the navel output. Further, the "+" side terminals of the operational amplifiers 25a, 25b are connected to the input resistors 26a, 26b to the points A and B of the circuit that extends from the output line 19E of the constant voltage circuit 19 to the variable resistors 15a, 15b.
and the other electrolytic capacitor 2
It is grounded via 9a and 29b.

The input resistors 26a, 26b and the capacitor 29
a and 29b are for improving the response characteristics of the adder circuit 20 and preventing hunting during operation.

The meter drive circuit 30 is composed of a current mirror circuit in which the bases of two PNP transistors 37 and 38 are connected together, and the output terminal of the adder circuit 20 is connected to the collector and base of one transistor 37, and the output terminal of the adder circuit 20 is connected to the collector and base of one transistor 37. transistor 38
The collector of the transistor 37 is connected to the input terminal of the fuel display meter 4, and the emitters of the transistors 37 and 38 are grounded.

The fuel display meter 4 is, for example, a typical coil-resistance type meter, and has a needle that swings in proportion to the magnitude of the output current of the meter drive circuit 30.

In the above configuration, each of the variable resistors 15a,
Since the resistance value of 15b is large, the above points A and B
The voltage at the point is high, and each operational amplifier 25
The potential difference between the "+" and "-" terminals of the operational amplifiers 25a, 25b increases, and the output voltages of the respective operational amplifiers 25a, 25b increase accordingly.
A predetermined current i ₁ , i ₂ flows between each emitter and each collector due to the amplification action of , and their combined output current (i ₁ +i ₂ ) is output from the adder circuit 20 to the meter drive circuit 30. .

As a result, in the meter drive circuit 30, equal base currents (i ₁ +i ₂ ) flow symmetrically to the bases of both the transistors 37, 37, and the amplification action of the transistor 38 causes the combined output from the collector to the emitter. A current proportional to the current (i ₁ + i ₂ ) flows, and this current causes the fuel display meter 4 to
The pointer will swing toward the scale F side, which indicates that there is a large amount of fuel remaining, in accordance with the total amount of fuel in the fuel tank 1.

On the other hand, as the liquid level in each of the chambers 7A, 7B decreases, the resistance value of each of the variable resistors 15a, 15b decreases in accordance with the respective liquid level, and the point A,
Since the voltage at point B also becomes low, the "+" terminal and "-" of each of the operational amplifiers 25a and 25b are connected.
The potential difference between the terminals becomes smaller, and contrary to the above case, the current flowing from the emitter to the collector of each PNP transistor 23a, 23b increases in accordance with the drop in the liquid level, and a large current flows from the adder circuit 20 to the meter drive circuit 30. A composite output current (i ₁ +i ₂ ) is output, and as a result, a large current flows through the fuel display meter 4 through the meter drive circuit 30, and its pointer swings significantly toward the scale E side, which indicates that the fuel level is low. become.

As described above, the addition circuit 20 and the meter drive circuit 30 allow the total amount of fuel in the fuel tank 1 to be displayed on the fuel display meter 4.

Next, the discrimination circuit 40 determines whether the first chamber 7 on the suction side is affected by the turning or tilting of the vehicle even though there is still fuel remaining in the fuel tank 1.
This is to determine that only the liquid level of A has fallen below a predetermined lower limit level, and to drive the motor 10a for driving the fuel transfer pump 10 via the motor drive circuit 50.

This discrimination circuit 40 includes two operational amplifiers 31a and 31b, an inverter 32,
Consists of a NAND gate 33 and an inverter 34,
The output terminal of one operational amplifier 31a is connected to one input terminal of the NAND gate 33, and the output terminal of the other operational amplifier 31b is connected to one input terminal of the NAND gate 33.
The output terminal of the inverter 32 connected to the output terminal of the inverter 32 is connected to the other input terminal of the NAND gate 33, and the inverter 34 is further connected to the output terminal of the NAND gate 33.

The "+" terminal (reference side) of the operational amplifier 31a is connected to a voltage dividing point C that is obtained by dividing the voltage between the output line 19E of the constant voltage circuit 19 and the ground using voltage dividing resistors 27a and 28a, and is connected to a predetermined standard. While a voltage is applied to it, its "-" terminal is connected to the operational amplifier 2 of the adder circuit 20.
It is connected to the input circuit to the "+" terminal of 5a.

On the other hand, the above operational amplifier 3
The "+" terminal of 1b is connected between the output line 19E of the predetermined voltage circuit 19 and the ground by voltage dividing resistors 27b and 28.
A predetermined reference voltage is applied to the voltage dividing point D, and its "-" terminal is input to the "+" terminal of the operational amplifier 25b of the adder circuit 20. connected to the circuit.

Furthermore, the output side of the discrimination circuit 40 is connected to the base of an NPN transistor 35 for ON/OFF control of the motor drive circuit 50.

The motor drive circuit 50 includes a relay coil 36a of a relay 36 including a normally open relay switch 11 in a circuit from the battery power source 5 to the motor 10a.
One end is connected to the battery power supply 5, and an NPN transistor 35 is connected in series to the relay coil 36a, and when a predetermined current is output from the discrimination circuit 40 to the base of the transistor 35, the transistor 35 operates a relay 36 to close the relay switch (a contact) 11 and drive the motor 10a.

In the above configuration, when both the liquid level in the first chamber 7A and the liquid level in the second chamber 7B on the suction side of the fuel tank 1 are equal to or higher than a predetermined lower limit level, the variable resistor 15 of each float sensor 2A, 2B
Since the resistance values of a and 15b are both large and the voltages at points A and B are also high, the potential difference between the "-" and "+" terminals of each operational amplifier 31a, 31b becomes small, and each operational amplifier Due to the positive characteristics of the amplifiers 31a and 31b, their outputs both go to the "L" level, and one operational amplifier 31a outputs an "L" level signal to the NAND gate 33, while the other operational amplifier 31b outputs an "L" level signal. The “L” level signal is inverted by the inverter 32, and an “H” level signal is output to the other input terminal of the NAND gate 33.

Therefore, an "H" level signal is output from the NAND gate 33, which is inverted by the inverter 34, and an "L" level signal is input from the inverter 34, so that the transistor 35 is not turned on.

On the other hand, the first chamber 7A on the suction side
When both the liquid level in the second chamber and the liquid level in the second chamber are below the predetermined lower limit level, the relationship is opposite to that described above, and the discrimination circuit 40 outputs an "L" level signal, and the transistor 35 also outputs a "L" level signal. Does not turn on.

Next, when the liquid level in the first chamber 7A on the suction side is high and the liquid level in the second chamber 7B is low, an "L" level signal is output from one operational amplifier 31a to the NAND gate 33. The “H” level signal is inverted by the inverter 32, and the “L” level signal is sent to the NAND gate 33.
Therefore, an "H" level signal is output from the NAND gate 33 to the inverter 34,
Since the "L" level signal is output from the inverter 34, the transistor 35 is not turned on.

On the other hand, if the liquid level in the first chamber 7A on the suction side is below the predetermined lower limit level and above the lower limit level in the second chamber 7B, the voltage at point A is low and the voltage at point B is high. , an "H" level signal is output from one operational amplifier 31a.
At the same time, the "L" level signal output from the other operational amplifier 31b is inverted by the inverter 32, and the "H" level signal is output to the NAND gate 33. An "L" level signal is output from the inverter 34, and this is inverted by the inverter 34, so that an "H" level signal is output from the discrimination circuit 40. The transistor 35 is turned on and the relay 36 is inverted. is activated. Then, the above relay switch closes and motor 1
0a is activated, the fuel in the second chamber 7B is transferred to the first chamber 7A on the suction side by the fuel transfer pump 1.
Transferred by 0. Then, when the liquid level in the first chamber 7A on the suction side eventually reaches or exceeds the above-mentioned lower limit level, the discrimination circuit 40 outputs an "L" level signal in the same way as above.
Motor 10a stops at that point.

On the other hand, the display value control circuit 60 operates in conjunction with the relay switch 11 by excitation of the relay coil 36a of the motor drive circuit 50.
It is constituted by a relay switch 61 having a contact structure, and when the motor drive circuit 50 is operated, that is, the fuel transfer pump 10 is operated, the power supply to the fuel display meter 4 is cut off, and the fuel display meter is switched off. The pointer 4 is fixed at the previous display position and changes to new display values are prohibited. As a result, the pointer of the fuel display meter 4 is reliably prevented from swinging while the fuel transfer pump 10 is in operation.

(Effect of the invention) As explained above, the present invention allows the first chamber on the suction side, which is connected to the fuel supply pipe, and the second chamber, which is separated from this and has a different capacity, to be connected by a pipe that communicates with the first chamber and the second chamber, which is separated from this and has a different capacity. A two-chamber separated fuel tank for an automobile, which communicates with each other, and has a fuel transfer pump interposed in the communication pipe to send fuel from the second chamber to the first chamber, and each of the first chamber and the second chamber. a liquid level detection means provided in the fuel tank, an addition means for receiving the outputs of both of these liquid level detection means and adding the two outputs, and a liquid level display for receiving the output of the addition means and displaying the liquid level of the fuel tank. means, and the above-mentioned first
and a drive motor that drives the fuel transfer pump when the liquid level detected by the chamber-side liquid level detection means falls below a predetermined value, wherein the fuel transfer pump drive motor operates. a fuel transfer pump drive motor operation detection means for detecting the operation of the fuel transfer pump drive motor; and when the fuel transfer pump drive motor operation detection means detects the operation of the fuel transfer pump drive motor, an operation of changing the display value of the liquid level display means is prohibited. The fuel transfer pump drive motor operation detection means and the display value control means are comprised of two sets of interlocking contacts that turn ON and OFF in conjunction with mutually opposite states. It is something to do.

Therefore, according to the present invention, when the fuel transfer pump is operated and the fuel transfer pump drive motor is operating, the display value of the liquid level display means is always prohibited from changing, and is fixed at the previously displayed value. Therefore, even if fuel moves from the first chamber to the second chamber or from the second chamber to the first chamber due to turning of the vehicle or the like when the fuel transfer pump operates to transfer fuel, the displayed value of the liquid level will fluctuate. Nothing will happen.

Moreover, in the case of a configuration based on a pointer-type meter as described above, it is sufficient to simply cut off the power to the liquid level display means in response to the operation of the fuel transfer pump drive motor, and the memory, etc. Doesn't require any means at all.

Therefore, the fuel transfer pump drive motor operation detection means and display value control means for realizing the above-mentioned functions should also be configured extremely simply and at low cost by only using ON and OFF contacts that operate in reverse in conjunction with each other. I can do it.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a fuel gauge for a vehicle according to an embodiment of the present invention, FIG. 2 is a front view of the float sensor section of the fuel gauge for the vehicle, and FIG. 3 is a diagram of the fuel gauge for the vehicle. It is an electrical circuit diagram. 1...Fuel tank, 2A, 2B...Float sensor, 3...Control unit, 4...Fuel display meter, 6...Fuel supply pipe, 7A...First chamber in the fuel tank, 7B...Inside the fuel tank Second room, 9...
Communication pipe, 10...Fuel transfer pump, 10a...
... Motor, 11 ... Relay switch, 20 ... Addition circuit, 30 ... Meter drive circuit, 40 ... Discrimination circuit, 50 ... Motor drive circuit, 60 ... Display value control circuit, 61 ... Relay switch.

Claims (1)

[Scope of utility model registration request] A first chamber on the suction side, which is connected to the fuel supply pipe, and a second chamber, which is separated from the first chamber and has a different capacity, are communicated with each other by a communicating pipe, and the second chamber is connected to the first chamber through the communicating pipe. A two-compartment separated type fuel tank for an automobile that is equipped with a fuel transfer pump that sends fuel to the two chambers, a liquid level detection means provided in each of the first chamber and the second chamber, and a liquid level detection means for both of the two chambers. an addition means that receives the output of the means and adds the two outputs; a liquid level display means that receives the output of the addition means and displays the liquid level in the fuel tank; and a liquid level detection means on the first chamber side. and a drive motor that drives the fuel transfer pump when the liquid level at which the liquid is stored falls below a predetermined value. a detection means, and a display value control means for prohibiting the operation of changing the display value of the liquid level display means when the operation of the fuel transfer pump drive motor is detected by the fuel transfer pump drive motor operation detection means, A fuel gauge for a vehicle, characterized in that the fuel transfer pump drive motor operation detection means and the display value control means are constituted by two sets of interlocking contacts that are turned ON and OFF in mutually opposite states.