JPS6215489Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to an automatic drain fuel filter device used in vehicle engines, etc., and its feature is that the drain solenoid valve is controlled only when the ignition switch is in the accessory position. By making the circuit operable, automatic drainage is performed only when the engine is stopped, making it possible to prevent the drainage solenoid valve from malfunctioning due to vibrations of the vehicle, etc.

2. Description of the Related Art Conventionally, fuel filter devices are known in which a water level detection electrode detects when water separated by a filter body has accumulated above a predetermined water level and automatically drains the water.

However, in such devices, even if the water level is below a predetermined level, when the vehicle shakes due to road irregularities, the accumulated water may jump and touch the water level detection electrode, causing the drainage solenoid valve control to be interrupted. It was common for the circuit to malfunction and cause the drain solenoid valve to open.

The purpose of this invention is to improve the drawbacks of the conventional device described above, and to prevent the drain solenoid valve from opening while the vehicle is running.

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

FIG. 1 schematically shows the entire automatic drain fuel filter device 1, which includes a fuel filter 2, a water level detection plug 3, a drain electromagnetic valve 4, and a drain electromagnetic valve control circuit 5.

The fuel filter 2 has a filter body 12 held in the center of a casing 11 by a lid 15 and a set spring 18 from above and below, and the lid 15 is provided with a fuel inlet 14 and an outlet 13. Moisture and dust are removed from the fuel flowing in through the inlet 14 by the filter 12, and the fuel is sent to the engine body through the central outlet 13.

The lid plate 15 is supported by a shroud plate 16 crimped to the periphery of the casing 11, and the inlet 14 and the outlet 13 are connected to an O-ring provided between the lid 15 and the filter body 12. It is partitioned by a packing 17.

At the bottom of the casing where the water separated by the filter body 12 accumulates, a gasket 3 is attached to the first plug seat 19.
A water level detection plug is provided through 1, a high position water level detection electrode 32 is provided at its upper end, and a low position water level detection electrode 33 is provided at its lower end.

A drain solenoid valve 4 is provided on the second plug seat 20 via a packing 41, and opens and closes a drain passage 43 formed in the lower end of the casing.

The drain electromagnetic 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 47 that always biases the valve 44 in the closing direction (leftward in the figure). 45
is separated from the drainage passage 43' by a diaphragm 46.

As shown in FIG. 2, the drain solenoid valve control circuit 5 consists of two circuits that are switched by a power switching relay RL ₂ .
When the SW is in the accessory position ACC, the drain solenoid valve 4 is opened and closed by signals from the water level detection electrodes 32 and 33, and the ignition position is
When in IG, a signal from the high-position water level detection electrode 32 indicates whether or not drainage is necessary.

Now, when the ignition switch SW is turned to the accessory position, since relay RL ₂ does not operate, the power supply 52 is connected to the lower circuit and becomes operational.

When the water separated by the filter 12 has accumulated up to the high level detection electrode, current flows through the water and switches the transistors T ₃ and T ₄ .
conducts, energizes the relay RL ₃ , and energizes the excitation coil 45 of the drain electromagnetic valve 4 to start draining.

At the same time, the water level detection electrode 32 is switched to 33, and the indicator lamp IL is lit through the diode _D5 to indicate that the water is being drained.

When drainage is completed and current no longer flows to the low water level detection electrode 33, the relay RL ₃ returns to the state shown in the figure, the drainage solenoid valve 4 closes, and the indicator lamp IL lights up.
also disappears.

When you switch the ignition switch SW to the ignition position IG and start the engine,
Power supply switching relay RL ₂ operates, switching the power supply circuit and making the upper circuit ready for operation.

When the water accumulated in the lower part of the casing increases to the level of the high position water level detection electrode 32, the switching transistor _T1 becomes conductive and the capacitor _C1 is charged through the resistor _R5 .

When the capacitor _C1 is charged continuously for a predetermined period of time (for example, several seconds), the switching transistor
The base potential of T ₂ rises and conducts, causing relay LR ₁ to operate.

When relay LR ₁ operates, a self-holding circuit is formed, which lights up the indicator lamp IL to indicate the need for drainage, and also grounds the connection point with resistors R ₁ and R ₃ to prevent the high water level. Prevent current from flowing to the detection electrode to prevent corrosion of the electrode due to electrochemical action.

Even though the accumulated water has not reached the high water level detection electrode 32, if the water touches the electrode due to vehicle shaking etc. and a current flows for a short time, the potential of the capacitor _C1 rises to the specified value. Moreover, since the battery is discharged when charging is interrupted, the indicator light will not be displayed incorrectly.

As explained above, in the automatic drain fuel filter device of this invention, the drain solenoid valve control circuit is enabled to operate only when the ignition switch is in the accessory position, so that automatic drain occurs only when the engine is stopped. This prevents the drainage solenoid valve from malfunctioning due to water splashing due to the shaking of the vehicle.

In the above embodiment, a low water level detection electrode is provided to control the end of the operation of the drain solenoid valve, but if the drain solenoid valve is designed to automatically close after a certain amount of time required for drainage has elapsed after it is opened, the low water level detection electrode will not be necessary.

[Brief explanation of drawings]

Fig. 1... A vertical sectional view of an automatic drain fuel filter device which is an embodiment of this invention, Fig. 2... A wiring diagram of the drain solenoid valve control circuit 1... Automatic drain fuel filter device, 2... Fuel filter, 3... Water level detection plug, 4... Drain solenoid valve, 5... Drain solenoid valve control circuit, 12... Filter body, 32... High position water level detection electrode, 45... Excitation coil, SW... Ignition Switch, RL ₂
...Power switching relay.

Claims (1)

[Scope of utility model registration request] In a fuel filter device equipped with a fuel inlet and outlet, a filter body, a drain solenoid valve, etc., the drain solenoid valve control circuit is operable only when the ignition switch is in the accessory position. Automatic drain fuel filter device.