JPS58119960A - Fuel tank - Google Patents

Abstract

PURPOSE:To prevent water in a fuel tank from being sucked into a suction pipe, by providing a subtank in the fuel tank at the lower part thereof and by arranging the blow-off port of a return pipe along the inner peripheral wall of the subtank so that the blow-off port is directed in the peripheral direction of the subtank. CONSTITUTION:The suction port 3 of a suction pipe is arranged in the center part of a cylindrical subtank 10 disposed on the bottom part of a feul tank, for sucking fuel by means of a pump. The blow-off port of a return pipe 9 is arranged along the inner peripheral wall of the subtank so that the blow-off port is directed in the peripheral direction of the subtank for generating swirl flow in the subtank by means of superfluous fuel returned from the pump, thereby water mixed in fuel is separated from fuel under centrifugal force and therefore, water is prevented from being sucked into the suction pipe.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel tank that can prevent water in the fuel tank from being sucked into a suction pipe.

Generally, automobile fuels such as gasoline contain water, so water accumulates at the bottom of the fuel tank, and when this water is sucked into the suction pipe by the pump, it can cause problems when the car is parked overnight in the winter. etc., the suction pipe is blocked and fuel cannot be supplied to the engine, resulting in the problem that the engine will not start. Conventionally, in order to prevent the water in the fuel tank from being sucked into the suction pipe, a shielding plate is provided between the suction port of the suction pipe, which opens near the bottom plate of the fuel tank, and the bottom plate. There was a device that prevented the water accumulated in the suction pipe from being sucked into the suction pipe (Utility Model Publication No. 45824/1983).

However, although the conventional fuel tank described above is effective in preventing the water accumulated at the bottom of the fuel tank from being sucked in, there is a problem in that the water mixed in the fuel is sucked in together with the fuel.

This invention was made in view of the problems of the conventional ones as described above, and a cylindrical sub-tank is provided at the bottom of the fuel tank, and the suction port of the suction pipe is arranged in the center of the sub-tank. By arranging the outlet of the return pipe toward the circumferential direction on the inner circumferential wall of the sub-tank, and generating a swirling flow in the sub-tank by excess fuel returned from the pump, It is an object of the present invention to provide a fuel tank in which water mixed in fuel is separated from the fuel by centrifugal force and water is prevented from being sucked into a suction pipe.

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

1 to 4 skip the first embodiment of the present invention. First, in FIG. 1 showing the fuel supply system of the engine, 1 is a fuel tank, and the fuel 11 in the fuel tank 1 is placed in the middle. The fuel is sucked into the pump 2 through a suction pipe 3 having a filter 4, supplied from the pump 2 to the float chamber 6a of the carburetor 6 via the fuel supply passage 5, and sucked out by the intake negative pressure of the engine 7 in the carburetor 6. vaporized,
It is mixed with air from the air cleaner 8 and sucked into the engine 7. Further, among the fuel sucked into the pump 2, surplus fuel when the liquid level in the float chamber 6a reaches a predetermined level is transferred to the fuel tank 1 through the return/guive 9 as surplus fuel. I'll take my turn to send it back. The attachment of the suction nozzle 3 and the one-turn pipe 9 to the fuel tank 1 is carried out by penetrating and fixing these pipes 3 and 9 to the ceiling &1a of the tank 1.

As shown in FIGS. 2 to 4, the bottom plate 1b of the fuel tank 1 is formed with a trapezoidal cross section r[P]-shaped convex IC, and above the convex aIC. A cylindrical sub-tank 10 is disposed therein, which is slightly larger than the convex portion IC, and a gap 12 between the lower end of the outer peripheral portion 10a and the bottom plate 1b serves as a communication port for communicating the inside and outside of the sub-tank 10. is provided, and further the upper part 10b
A communication port 10C of fine sand is also formed in the opening.

Further, the suction pipe 3 is fixed to the center portion 10f of the upper part 10b of the sub-tank 10, and the suction port 3a of the suction pipe 3 is connected to the sub-tank 10.
The return pipe 9 is fixed through the upper part 10b, and the tip s9m of the return pipe 9 is curved in the circumferential direction of the inner peripheral wall 10g of the sub-tank 10. The air outlet 9b is open toward the circumferential direction.

In this way, the sub-tank 10 is suspended and fixed to the fuel tank 1 by the suction pipe 3 and the return pipe 9.

According to the fuel tank having such a configuration, when there is a certain amount of fuel 11 in the fuel tank 1, the gap 12 between the bottom plate 1b of the fuel tank 1 and the outer peripheral part 10a of the sub-tank 10
Alternatively, the fuel 11 enters and enters the sub-tank 10 from the communication port 10C of the outside 10b of the sub-tank 10, so that the fuel 11 is always present in the sub-tank 10. The surplus fuel returned from the pump 2 is transferred to the return pipe 9.
Since the air is blown from the air outlet 9b in the circumferential direction of the inner circumferential wall 10g of the sub-tank 10, as shown in FIG.
Since water in the fuel has a higher specific gravity than the fuel, it is separated from the fuel by the centrifugal force caused by the swirling flow, and this separated water flows into the outer circumference 10 of the sub-tank 10.
It is discharged to the outside of the sub-tank 10 through the gap 12 between the tank a and the bottom plate 1b. Therefore, the only fuel that remains in the sub-tank 10, especially near the center, is the fuel from which water has been completely separated and removed, and only such fuel is sucked into the suction pipe 3 provided in the center of the sub-tank 10, and the pump 2 is It will be supplied to the engine 7 via the engine.

In the above embodiment, the sub-tank 10 was fixed to the ceiling plate 1a of the fuel tank 1 by the suction pipe 3 and the return pipe 9, but the sub-tank 10
There are various other methods for supporting the fuel tank 1. For example, the fuel tank 1 may be welded and fixed to the bottom plate 1b of the fuel tank 1 via a diffused support.

FIG. 5 shows a second embodiment of the invention, in which the first
F8! The same reference numerals as in FIGS. J to 4 indicate the same things. In this embodiment, the sub-tank 10 is provided with a bottom plate 10d, which is fixed to the protrusion IC of the bottom plate 1b of the fuel tank 1 by, for example, welding, and is fixed to the lower end of the outer peripheral part 10a of the sub-tank 10. In this embodiment, water mixed in the fuel is separated and separated from the fuel by the swirling flow inside the sub-tank 10. , is discharged from the communication port 10e to the outside of the sub-tank 10,
Only fuel that does not contain water is sucked into the suction vibe 3.

As described above, according to the fuel tank according to the present invention, the sub-tank is provided at the lower part of the fuel tank, and the outlet of the return vibe is arranged on the inner circumferential wall of the sub-tank toward the layer direction, so that the surplus from the pump can be removed. Since the fuel causes a swirling flow in the sub-tank, moisture mixed in the fuel can be reliably separated from the fuel, and only fuel that does not contain moisture can be supplied to the engine.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a fuel supply system for an engine including a fuel tank according to the present invention, FIG. 2 is a perspective view of a main part of a first embodiment of the present invention, and FIG. 3 is a main part of the above embodiment. cross-sectional side view of
FIG. 4 is a cross-sectional plan view of the main part of the above embodiment, and FIG. 5 is a cross-sectional side view of the main part of the second embodiment of the present invention. 1... Fuel tank 2... Pump 3... Suction vibe 3a... Suction port 7... Engine 9... Return vibe 9b... 1lfjo
10...Subtank 10M...Outer periphery
10b...Top 10C...Communication port 10g
... Inner peripheral wall 11 ... Fuel 12 ... Communication port Patent applicant Toyo Kogyo Co., Ltd. agent Patent attorney Ken Hayase - Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] (1) A cylindrical sub-tank is installed at the bottom of the fuel tank, communication ports are formed at the bottom and top of the outer periphery of the sub-tank, and a suction pipe for supplying fuel to the engine with a pump is located in the center. A suction port is arranged, and a return pipe outlet for returning surplus fuel from the pump is arranged in the circumferential direction on the inner circumferential wall of the sub-tank, and the surplus fuel from the return pipe creates a swirling flow inside the sub-tank. A fuel tank characterized in that it is designed to give.