JPH0767960B2 - Draining device with level gauge for fuel tank - Google Patents

Description

The present invention relates to a fuel tank level for displaying the level of fuel stored in a fuel tank and pumping out and discharging water accumulated in the fuel tank. It relates to a drainage device with a gauge.

[Prior Art] Conventionally, as a level gauge for displaying the level of fuel stored in a fuel tank, a pair of electrodes are vertically provided in the fuel tank as disclosed in JP-A-63-131028. Things are known. This level gauge utilizes the fact that the capacitance between both electrodes changes according to the level of the fuel interposed between both electrodes, converts this change in capacitance into a change in voltage, and outputs the output voltage. The fuel level in the fuel tank is displayed accordingly. Further, when water is present between both electrodes, the capacitance changes greatly, and this change is captured to indicate that water has accumulated in the fuel tank.

On the other hand, as a device for draining water accumulated in the fuel tank,
As disclosed in Japanese Utility Model Application Laid-Open No. 61-128133, a water sensor for detecting the water level is provided, and the discharge device is operated based on the change in resistance detected by the water sensor to provide an electromagnetic sensor provided at the bottom of the fuel tank. It is known to discharge water through a valve.

[Problems to be Solved by the Invention] However, such a level gauge and a drainage device are
Must be attached to the fuel tank separately,
There was a problem that the installation was troublesome. Also, dust and rust easily accumulate on the bottom of the fuel tank.
These are mixed. Therefore, when this water is discharged from the solenoid valve installed at the bottom of the fuel tank, dust and rust will clog the solenoid valve, and the solenoid valve will not close completely. It may be taken out. In addition, dust and rust may adhere to the flow channel, narrowing the flow channel, and reducing the drainage function.

Therefore, the present invention aims to solve the above problems,
To provide a drainage device with a level gauge for a fuel tank, which can prevent the water drainage function from being deteriorated due to dust or rust at the bottom of the fuel tank, can properly drain the water accumulated at the bottom of the fuel tank, and is easy to install. It is in.

[Means for Solving the Problems] In order to achieve the above object, the present invention has the following configurations as means for solving the problems. That is, a pair of electrodes are provided vertically toward the bottom of a fuel tank for storing fuel, and a conversion means for outputting a voltage corresponding to an electrostatic capacitance that changes according to the level of the fuel interposed between the electrodes is provided. A level display means for displaying the level of the fuel in the fuel tank according to the output of the conversion means is provided, and the pump pipe extending from the upper port of the fuel tank toward the bottom is insulated from the pump pipe. And a drainage pump for rotating the pump shaft inserted through the pump pipe to discharge the pump shaft to the outside of the fuel tank, wherein the pair of electrodes are formed by the pump pipe and the pump shaft. In response to a change in capacitance when water is present between the electrodes, when the output voltage from the conversion means changes,
This is the structure of a drainage device with a level gauge for a fuel tank, which is provided with a control means for driving the drainage pump.

[Operation] In the drainage device with a level gauge for a fuel tank having the above-described configuration, the conversion means corresponds to the electrostatic capacitance which changes depending on the level of the fuel interposed between both electrodes formed by the pumping pipe and the pump shaft. Output the voltage. Then, the level display means displays the fuel level according to the output voltage from the conversion means. Further, the control means drives the water drain pump when the output voltage from the conversion means changes in accordance with the change in the electrostatic capacitance when water is present between the electrodes. Then, the water drain pump pumps water from the bottom of the fuel tank through the pump pipe and discharges the water to the outside of the fuel tank.

Embodiments Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a sectional view of a drainage device with a level gauge for a fuel tank according to an embodiment of the present invention. 1 is a fuel tank,
It stores kerosene or the like as fuel, and has a rectangular parallelepiped shape in this embodiment. On the upper side of the fuel tank 1, there is provided a cylindrical supply port 2 into which fuel can be injected, and a main body 4 that is detachably fitted to the supply port 2 is provided with a supply port 2. Is installed so as to close the. The main body 4 is composed of two layers, that is, a metal lower body 4a fitted into the supply port 2 and an electrically insulating upper body 4b laminated thereon. Then, in the lower portion 4a of the main body, a fitting hole 6 opened toward the inside of the fuel tank 1 is formed.
Is formed, and one end of a straight metal-made pumping pipe 8 is fitted into the fitting hole 6.

The pumping pipe 8 is connected to the bottom of the fuel tank 1 from the supply port 2.
It extends toward 1a, and a suction member 10 is electrically insulated and attached to a tip 8a thereof. The suction member 10 is provided with a suction port 12 opening toward the bottom 1a of the fuel tank 1 on an extension line of the pumping pipe 8, and the inside of the suction port 12 is made hollow to pump up with the suction port 12. It communicates with the pipe 8.

Then, the metal pump shaft 14 that penetrates the inside of the upper body 4b, the fitting hole 6, and the pumping pipe 8 in the axial direction and reaches the inside of the suction member 10 at its tip is electrically connected to the lower body 4a of the body. It is rotatably supported on the upper part 4b of the main body while being insulated. A fin 16 is attached to the tip of the pump shaft 14, and a rotating shaft of a motor 20 is connected to the other end of the pump shaft 14 via a coupling 18. By rotating the motor 20, the pump shaft 14 and the fins 16 are rotated to suck the water through the suction port 12 and discharge the water into the pumping pipe 8.

In addition, on the upper part 4b of the main body around the pump shaft 14, brush guide
24 is provided, and the electrode brush is attached to this brush guide 24.
Pump shaft with electrode brush 26 attached and rotating with electrode brush 26
An electrical connection is established between 14 and. A water level detecting sensor 27 is formed by the pumping pipe 8, the pump shaft 14, and the electrode brush 26.

In this embodiment, since the pumping pipe 8 and the pump shaft 14 also serve as a pair of electrodes, they can be inserted from the supply port 2. Therefore, even in the existing fuel tank 1, the supply port 2
It can be easily attached by inserting these from.

On the other hand, the fitting hole 6 extends from the lower body 4a to the upper body 4b.
A communication hole 28 communicating with the pumping pipe 8 via the through hole is formed, and a water conduit 25 is formed by the fitting hole 6, the pumping pipe 8, and the communication hole 28. Also, the first valve seat 29 is provided in the communication hole 28.
A return hole 30 communicating with the fuel tank 1 and opening toward the inside of the fuel tank 1 is formed. Further, a drainage hole communicating with the communication hole 28 via the second valve seat 31 and opened to the outside of the fuel tank 1.
32 are formed.

The two valve seats 29, 31 are formed to face each other, and the valve body 34 slidably supported by the upper portion 4b of the main body has the two valve seats 29, 3
1 is provided so that each can be seated. An armature 36 is connected to the valve body 34, and the armature 36 is moved by an urging force of a spring 38 and an electromagnetic force of a coil 40. And spring 38
The valve element 34 can be switched to the return position where the valve element 34 is seated on the second valve seat 31 by the urging force of, and to the drain position where the valve element 34 is seated on the first valve seat 29 by the electromagnetic force generated by the excitation of the coil 40. It is configured to be able to. These, both valve seats
An electromagnetic switching valve 42 is formed by 29, 31, the valve element 34, the armature 36, the spring 38, and the coil 40.

Further, the electrode 44, which penetrates the upper part 4b of the main body and has its tip exposed in the communication hole 28, is attached so as to face the lower part 4a of the main body. This electrode 44, water sensor
Forming 45. The electrode 44, the motor 20, the electrode brush 26, the coil 40, etc. are connected to a circuit board 48 attached to the upper portion 4b of the main body. A cover 46 is attached to the upper portion 4b of the main body so as to cover them.

An electronic control circuit 50 is formed on the circuit board 48, and the electronic control circuit 50 includes a stabilized power supply circuit 52 connected to an external power supply 51, as shown in FIG. Connected to the circuit. Then, the electrode brush 26,
It is connected to a capacitance-voltage conversion circuit 54 (hereinafter referred to as C-V conversion circuit 54), and the pumping pipe 8 is at the bottom of the main body.
It is grounded through 4a. The pumping pipe 8 and the pump shaft 14 form a pair of electrodes, and the C-V conversion circuit 54 changes the electrostatic capacitance between the pumping pipe 8 and the pump shaft 14 into a voltage. It is well known that it is converted into a change and output.

Since the relative permittivity of air is smaller than the relative permittivity of fuel, the electrostatic capacity thereof decreases as the level of the fuel stored in the fuel tank 1 decreases. Further, since the relative permittivity of water is very large, if water is present between the pumping pipe 8 and the pump shaft 14, its electrostatic capacitance becomes very large. In the C-V conversion circuit 54 of the present embodiment, the output voltage increases as the electrostatic capacitance increases in response to the change in the electrostatic capacitance.

The CV conversion circuit 54 is connected to the display voltage comparison circuit 56, and the display voltage comparison circuit 56 compares the voltage from the CV conversion circuit 54 with a plurality of preset voltages. hand,
The signal is output according to the comparison result. And
The display voltage comparison circuit 56 is connected to the fuel level display circuit 58, and the fuel level display circuit 58 emits any one of the light emitting diodes 59a to 59d corresponding to the comparison result in response to the comparison result signal. It is what makes me. For example, when the fuel tank 1 is full and the output voltage from the CV conversion circuit 54 is maximum, all the light emitting diodes 59a to 59d are caused to emit light. As the output voltage decreases, the light emitting diode
When the output voltage from the C-V conversion circuit 54 in which the fuel tank 1 is empty is the minimum, the light emission of all the light emitting diodes 59a to 59d is stopped to stop the fuel emission. It is supposed to display the level of.

Further, the CV conversion circuit 54 is also connected to the detection voltage comparison circuit 60, and the detection voltage comparison circuit 60 outputs the output voltage from the CV conversion circuit 54 as shown in FIG. The output voltage is configured to change from a low level to a high level when it becomes a very large value. The detection voltage comparison circuit 60 is connected to the water detection display circuit 62, and the water detection display circuit 62 causes the light emitting diode 64 to emit light when the output voltage of the detection voltage comparison circuit 60 is at a high level. It is configured to output a signal.

On the other hand, the detection voltage comparison circuit 60 is also connected to the differentiation circuit 66, and the output voltage from the detection voltage comparison circuit 60 is input to the differentiation circuit 66, differentiated by the differentiation circuit 66, and the trigger pulse is output. To be done. This trigger pulse is input to the monostable pulse generation circuit 68 and
Outputs a pulse signal having a predetermined time T width when this trigger pulse is input. The predetermined time T is set to be longer than the time required for at least the fuel, water, etc. near the tip 8a of the pumping pipe 8 to reach the electrode 44 when the water drain pump 22 is operated. There is.

The electrode 44 is connected to the drainage voltage comparison circuit 70, the drainage voltage comparison circuit 70, the resistance value changes with the resistance value between the electrode 44 and the main body lower part 4a grounded. When the output voltage decreases, the output voltage changes from low level to high level. Then, the output voltage is input to the solenoid valve drive circuit 72, and the solenoid valve drive circuit 72 outputs a signal for exciting the coil 40 of the solenoid switching valve 42 according to the change in the voltage.

In addition, the monostable pulse generation circuit 68 and the drain voltage comparison circuit
The signal from 70 is input to the OR circuit 74, and when the signal is input from one of the monostable pulse generation circuit 68 or the drainage voltage comparison circuit 70, the signal is output to the pump drive circuit 76. There is. In this pump drive circuit 76, when a signal is input, a drive signal is output to the motor 20 to drive the motor 20 to rotate.

In this embodiment, a terminal 80 is provided which can take out the output signal from the C-V conversion circuit 54 to the outside.
This terminal 80 is connected to a display voltage comparison circuit (not shown) provided at a remote place such as indoors, and a fuel level display circuit and a light emitting diode similar to those described above are provided so that fuel can be used indoors. The level of may be displayed.

Next, the operation of the drainage device with a level gauge for a fuel tank according to the present embodiment described above will be described.

First, the main body 4 and the like are removed from the supply port 2, and the fuel tank 1
, Fuel such as kerosene is injected from the supply port 2, the fuel is consumed, and new fuel is additionally injected each time it is consumed. When the fuel tank 1 is fully filled with fuel, the capacitance between the pumping pipe 8 and the pump shaft 14 is large because the fuel level is maximum. According to the electrostatic capacity at this time, the C-V conversion circuit 54 converts it into a voltage corresponding to the electrostatic capacity and outputs it to the display voltage comparison circuit 56. Then, the display voltage comparison circuit 56 outputs a predetermined signal to the fuel level display circuit 58 in response to this voltage to cause all the light emitting diodes 59a to 59d to emit light. Further, when the fuel level decreases as the fuel is consumed, the light emitting diodes 59b to 59d corresponding to the fuel level at that time are caused to emit light.

Further, the water mixed with the fuel is separated, and the water having a larger specific gravity than the fuel is collected at the bottom 1a of the fuel tank 1, and at the boundary, the fuel layer is in the upper layer and the water layer is in the lower layer. Occurs.
Then, as the fuel is consumed, the amount of water accumulated at the bottom 1a increases, the water level rises, and the water level rises at the tip 8a of the pumping pipe 8.
When the detected water level reaches up to, the electrostatic capacitance between the pumping pipe 8 and the pump shaft 14 greatly increases.

As a result, as shown in FIG. 3, the output voltage from the CV conversion circuit 54 greatly increases, and the detection voltage comparison circuit 60
In response to this, outputs a high level signal to the differentiating circuit 66, and the differentiating circuit 66 outputs a trigger pulse.
Then, the monostable pulse generating circuit 68 receives the trigger pulse and outputs a pulse having a time T width. As a result, a signal is output from the OR circuit 74 to the pump drive circuit 76, and the pump drive circuit 76 outputs a rotation drive signal to the motor 20.

Therefore, the motor 20 rotates, the coupling 18, the pump shaft
The fin 16 is rotated via 14. By the rotation of the fins 16, the water at the bottom 1a of the fuel tank 1 is pumped up through the suction port 12, the pumping pipe 8, the fitting hole 6, and the communication hole 28.

At this time, even in the pumping pipe 8, fuel exists in the upper layer and water in the lower layer in a separated state, and when the water is pumped up,
First, the fuel rises along the pumping pipe 8. This fuel passes through the pumping pipe 8 and the fitting hole 6 and passes through the communication hole 28.
Even if it enters and is interposed between the electrode 44 and the lower part 4a of the main body, the resistance value therebetween is large. Therefore, the output voltage from the drainage voltage comparison circuit 70 is at a low level, and the solenoid valve drive circuit 72
No drive signal is output from. Therefore, the valve element 34 of the electromagnetic switching valve 42 is in a state of being seated on the second valve seat 31 by the urging force of the spring 38, and the communication hole 28 and the return hole 30 communicate with each other. As a result, the fuel is returned from the pumping pipe 8, the fitting hole 6, and the communication hole 28 to the inside of the fuel tank 1 through the return hole 30.

On the other hand, with this pumping, the water level becomes lower than the tip 8a of the pumping pipe 8, and the electrostatic capacitance between the pumping pipe 8 and the pump shaft 14 is greatly reduced. However, since the monostable pulse generation circuit 68 outputs a pulse having a time T width,
At least during this time T, the operation of the motor 20 is continued.

While this operation is continued, water is pumped through the pumping pipe 8 following the fuel, and the tip of the pumping pipe 8 is
When the water in 8a is supplied to the communication hole 28 through the fitting hole 6 and reaches the electrode 44, the resistance value between the electrode 44 and the lower portion 4a of the main body becomes small. As a result, the output voltage from the drainage voltage comparison circuit 70 becomes high level, and the solenoid valve drive circuit 72 receives this signal and outputs a drive signal for exciting the coil 40. When the coil 40 is excited, the armature
36 moves against the urging force of the spring 38 to seat the valve element 34 on the first valve seat 29.

Further, before the output from the monostable pulse generation circuit 68 becomes low level, a high level signal is output from the drain voltage comparison circuit 70 to the OR circuit 74. As a result, the drive signal is continuously output from the pump drive circuit 76 to the motor 20, and the operation of the drainage pump 22 is continued.

In this way, the communication hole 28 and the drain hole 32 are communicated, and the return hole 30
The communication with and is cut off, and the water that has passed through the communication hole 28
The water is discharged from the fuel tank 1 through the drain hole 32 from the fuel tank 28. Then, the water level in the fuel tank 1 is lowered, the fuel is sucked from the suction port 12, and the fuel follows the water and the pump pipe 8
Pumped from. When the fuel is supplied from the pumping pipe 8 through the fitting hole 6 to the communication hole 28 and reaches the electrode 44, the resistance value between the electrode 44 and the lower portion 4a of the main body increases, and the drainage voltage comparison The output voltage from the circuit 70 becomes low level.

As a result, first, the excitation of the coil 40 by the solenoid valve drive circuit 72 is stopped. Further, since the time T has elapsed during this time, the input signals to the OR circuit 74 from the monostable pulse generation circuit 68 and the drainage voltage comparison circuit 70 both become low level, and the motor driven by the pump drive circuit 76. The drive of 20 is stopped. Therefore, the electromagnetic switching valve 42 blocks communication between the communication hole 28 and the drain hole 32, and the communication hole 28 and the return hole 30 communicate with each other. Further, the operation of the water drain pump 22 is stopped, and the pumping is completed.

In this embodiment, the display voltage comparison circuit 56, the fuel level display circuit 58, and the light emitting diodes 59a to 59d function as level display means, and the detection voltage comparison circuit 60, the differentiation circuit 66, the monostable pulse generation circuit 68, The OR circuit 74 and the pump drive circuit 76 serve as control means.

As described above, the drainage device with a level gauge for the fuel tank according to the present embodiment changes the electrostatic capacity according to the level of the fuel interposed between the pumping pipe 8 and the pump shaft 14,
Display fuel level. Further, if water is present between the pumping pipe 8 and the pump shaft 14, the electrostatic capacity of the water greatly changes. At that time, drive the water drain pump 22,
Water in the fuel tank 1 is pumped upward from the bottom 1a of the fuel tank 1 and discharged to the outside of the fuel tank 1.

Therefore, the pumping pipe 8 as a pair of electrodes and the pump shaft
The fuel level is displayed and the water is discharged according to the change in capacitance between 14 and. Therefore, even in the existing fuel tank 1, the pumping pipe 8 and the pump shaft 14 from the supply port 2
Can be easily attached by simply inserting etc. Further, the water accumulated at the bottom 1a of the fuel tank 1 is forcibly pumped up from the bottom 1a by the water draining pump 22 to obtain the fuel tank 1
Drain outside. As a result, even if dust or rust is mixed in the pumped water, dust or rust adheres to the pumping pipe 8, the fitting hole 6, the communication hole 28, the drain hole 32, the valve body 34, the second valve seat 31, etc. It is discharged to the outside without doing. Therefore, it is possible to prevent deterioration of the drainage function due to adhesion of dust and rust. Further, the fuel is pumped from the bottom 1a of the fuel tank 1 and discharged from the supply port 2 to the outside. Therefore, when the operation of the water drain pump 22 is stopped, the pumping of water is stopped, and the communication hole 28 and the drain hole are opened by the electromagnetic switching valve 42.
Even if the communication with 32 is not completely cut off, water and fuel will not leak out.

The present invention is not limited to the embodiments as described above, and can be implemented in various modes without departing from the gist of the present invention.

[Effects of the Invention] As described in detail above, the drainage device with a level gauge for a fuel tank of the present invention forms a pair of electrodes by a pumping pipe and a pump shaft, and based on the capacitance of both electrodes. While displaying the fuel level, when water accumulates at the bottom of the fuel tank, the water is forcibly pumped up by the water draining pump through the pumping pipe and automatically drained out of the fuel tank. Since the pumping pipe and the pump shaft also serve as the electrode and the passage for discharging water, the device is downsized and can be easily attached to the fuel tank.In particular, even if it is an existing fuel tank, it can be inserted into the supply port. Since it can be installed by attaching it, it is easy to install. Further, dust and rust do not adhere, the drainage function can be prevented from lowering, and when pump operation is stopped, pumping of water is stopped and fuel does not leak.

[Brief description of drawings]

FIG. 1 is a sectional view of a drainage device with a level gauge for a fuel tank as one embodiment of the present invention, FIG. 2 is a block diagram of an electronic control circuit of this embodiment, and FIG. 3 is each circuit of this embodiment. 3 is a time chart explaining the state of signals in FIG. 1 ... Fuel tank, 2 ... Supply port 6 ... Fitting hole, 8 ... Pump pipe 14 ... Pump shaft, 22 ... Drainage pump 25 ... Water conduit, 50 ... Electronic control circuit

Claims (1)

[Claims] 1. A conversion means for vertically arranging a pair of electrodes toward the bottom of a fuel tank for storing fuel and outputting a voltage corresponding to an electrostatic capacitance which changes depending on the level of the fuel interposed between the electrodes. The pump pipe is provided with level display means for displaying the level of the fuel in the fuel tank according to the output of the conversion means, and the pump pipe is attached to the pump pipe extending from the upper port of the fuel tank toward the bottom. And a drainage pump that rotates an inserted pump shaft and discharges it outside the fuel tank through the pumping pipe, wherein the pair of electrodes is formed by the pumping pipe and the pump shaft. Then, according to the change in capacitance when water is present between the electrodes, when the output voltage from the conversion means changes,
A drainage device with a level gauge for a fuel tank, comprising a control means for driving the drainage pump.