JPS58210356A - Automatic-drainage fuel filter device - Google Patents

Abstract

PURPOSE:To prevent a coil of a solenoid valve from burning damage by providing a condenser and a resistance in parallel with a drainage solenoid valve control circuit of a fuel filter for reducing the excessive current required to open a drainage solenoid valve. CONSTITUTION:The separation water level in a filter 15 is risen, Tr1 is connected by a detecting electrode 32, and TH is ignited to connect Tr3. Then, current is supplied in the circuit of a condenser C and a resistance R10, and during this charging time, a valve 44 is opened for draining. After the condenser C is charged, current is supplied to an excitation coil via the resistance 10, and the current after the charging is set by the resistance 10. When water is drained, Tr2 is disconnected by a detection electrode 33, and TH and Tr3 are also disconnected to intercept the current of an excitation coil 45 and close the valve 44. This construction permits to reduce the excessive current required to open a drainage solenoid valve and prevent the coil of the solenoid valve from burning damage.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel filter with an automatic drainage device and equipped with a water level detection means for use in an internal combustion engine.

The fuel filter has the function of removing dust contained in fuel oil such as light oil and separating water from the fuel oil. A water droplet that boils this separated water is installed at the bottom of the fuel filter, and when the water level exceeds a certain level, it notifies the user of the water level of the separated water and automatically opens the drain solenoid valve. A device is known that discharges water that has been boiled down from the bottom of the fuel filter to the outside.

However, in such a device, the excessive current required to open the drain electromagnetic valve continues to flow until the drain is completed, resulting in large power consumption of the power source.

Furthermore, if the accumulated water contains garbage, the drainage hole will be partially blocked by the garbage, making it take a long time to drain the water, and the above-mentioned excessive current will continue to flow through the excitation coil in the drain solenoid valve, causing the excitation coil to However, the excitation coil had to be made thicker and larger.

The present invention is an automatic drainage system that eliminates the drawbacks such as pitting.

The present invention provides a fuel filter having a device, which is provided with a circuit that immediately reduces the current to the valve holding the KFM4 valve after the drain solenoid valve is opened.

In FIG. 1, an automatic drain fuel filter device 1 comprises a fuel filter main body 2, a water level detection device 3, a drain 'ILa valve 4, and a drain electromagnetic valve control circuit 5. -1 The fuel filter main body 2 has a filter body 12 pressed by a spring 17 disposed inside a metal cup-shaped casing 11, a shroud 16 tightened around the open end of the casing 11, and a fuel oil outlet 13. ,1
4 and a cover plate 15 provided with a sheet. The water level detection device 6 is provided with a high-position water level detection electrode 62 at the upper end of a synthetic resin cylinder, and a low-position water level detection electrode 63 at its lower end, and has terminals 54 and 35 connected to each electrode. , the metal casing 111 is inserted into the closed base. A plug seat 18 is provided at the bottom of the casing 11, and a drain electromagnetic valve 4 is disposed on the plug seat 18 via a packing 41 to open and close a drainage passage 43 formed in the plug seat 18. The drain valve 4 consists of a valve 44 with a gasket 42 at its tip, an excitation coil 45 that operates the valve 44, and a spring 46 that always biases the valve 44 in the closing direction. It is partitioned off from passages 45' and 4B.

The drain electromagnetic valve control circuit 5 is shown in FIG. 2. Reference numeral 52 is a power source whose one end is grounded, and one terminal 5'la of the switch 51 is connected to the non-grounded terminal of the power source 52. The anode side of the diode D1 is connected to the other terminal 51b of the switch 51, and the cathode side of the diode D1 is connected to the high position water level detection terminal 64 via resistors Rj and R2. It is also connected to the low water level detection terminal 65 via resistors R8 and R9. This is a ZnR varistor whose one end is connected to the switch terminal 51b and whose other end is grounded. A transistor Tr1 whose emitter is connected to the cathode terminal of the diode D1.
fi, its base is connected to the connection point of resistor R1 and resistor R2, and its collector is grounded via diode 1)2 and resistors R5 and R4. The thyristor TH whose gate is connected to the connection point of the resistor R5 and the resistor R4 is a transistor Tr whose anode is connected to the cand terminal of the diode D1.
2 through a resistor R6, and its cathode is grounded through a resistor R7. A resistor R5 is connected between the cathode and the gate of this thyristor T)I. Thyristor TH
The transistor Tr5 has its base connected to the connection point A of the resistor R7, and its collector is connected to the display circuit, and its emitter is grounded.

The display circuit has one end connected to the drain electromagnetic valve 4 through a parallel capacitor C and a resistor R connected to the timemate D1, and the other end of the diode DS1 indicator lamp LP arranged in parallel with this is connected to the transistor Tr5. Become.

In the self-draining fuel filter device 1 having such a structure, fuel flows into the casing 11 from the inlet 16 of the filter body 2, passes through the filter body 12, and flows out through the outlet 14. Water droplets in the fuel oil are separated by the filter 12 and collected at the bottom of the casing 11. - While the high-position water level detection electrode 32 at the upper end of the water level detection device 6 in the casing 11 is in contact with the fuel, the electrical conductivity of the fuel is small and the resistance between the detection electrode 32 and the metal casing 11 is extremely large. A potential difference necessary to operate the transistor Tr1 is not generated in the resistor R1, and the drain electromagnetic valve 4 is not operated.

When the separated water gradually rises and immerses the high-position water level detection electrode 32, a current flows from the electrode 62 to the metal casing 11 due to the highly conductive water. Then, a potential difference sufficient to operate the resistor Rj[) transistor Trl is generated, making the transistor Tr1 conductive. When the transistor Trl becomes conductive, the amplified current flows through the thyristor TH through the daughter resistor R3.
The current flows to the gate of , causing the thyristor TH to fire. The fired thyristor TH causes a current to flow through the base of the transistor Tr3, making the transistor Tr5 conductive.

When the transistor 'rr5 becomes conductive, a capacitor C disposed between the power supply 52 and the drain solenoid valve 4 and connected in parallel
A current flows through the circuit of resistor R1g.

Excitation coil 45 of charging time drain solenoid valve 4 of Conde Dosu C
The excessive current required to actuate valve 44 flows to open valve 44 and to the bottom of casing 11.

Start draining the accumulated water. At the same time, the display rung LP is lit to indicate that the water is being drained. After charging the capacitor C, the excitation coil 45 is energized via the resistor R1Q, so
The charging time of capacitor C is the capacitor C connected in parallel.
The time constant of 1 resistance J'11g is set, and the current flowing through the excitation coil 45 after charging is resistance.

Set the anti-R1 and other settings. During drainage, the current that is lower than that at the start of operation is maintained. When the water is discharged, the fuel oil deteriorates the electrical conductivity between the low water level detection electrode 35 and the metal casing 11, increasing the resistance and rendering the transistor Tr2 non-conductive. Then, thyristor TH,) transistor Tr
3 also becomes non-conductive, the current in the excitation coil 45 of the drain electromagnetic valve 4 is cut off, the valve 44 is closed, and the lamp LP is extinguished.

As described above, in the present invention, a capacitor and a resistor connected in parallel are arranged in the connection circuit between the power source and the drain solenoid valve. When the water separated by the filter reaches the high-position water level detection electrode and activates the drain 1'1a valve control circuit to open the drain solenoid valve, the capacitor is charged with an excessive current to open the valve. Just let time flow. After the photovoltaic operation, the current is reduced to a holding current that maintains the valve open using a parallel resistor, so it is possible to prevent the coil from generating heat due to the long-term overcurrent of 1M4 @ tc, and to reduce power consumption. Because it can prevent the excitation coil from generating heat,
It can be made into a shed, and the drainage solenoid valve itself can be made smaller and lighter.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view of an automatic drainage fuel filter device that is an embodiment of the present invention. FIG. 2 is a wiring diagram of the drainage solenoid valve control circuit. 1... Automatic drainage fuel filter device 2...
......Fuel filter 3...Bent water detection device 4...Drainage solenoid valve 5...
...Drainage solenoid valve control circuit 32...High water level detection electrode 33...Low water level detection electrode 45...Exciting coil 52...Power supply patent Applicant Tsuchiya Seisakusho Co., Ltd.

Claims (1)

[Claims] A filter body is housed in a liquid-tight housing made of a sheet having an inlet and an outlet and a metal cup-shaped casing, and a water level detection device and a drain solenoid valve control circuit between the drain solenoid valve and the power source are installed at the bottom of the casing. An automatic drainage fuel filter device characterized in that a capacitor and a resistor are arranged in parallel with each other.