JPS6230497Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sub-tank structure of a vehicle fuel tank used, for example, in a fuel circulation system in an automobile engine.

Generally, for example, the fuel tank of the fuel supply system in a vehicle equipped with an electronic fuel injection control system is provided with a sub-tank inside to prevent the low boiling point fraction in the fuel in the fuel supply system from turning into vapor at high temperatures. It's getting old. That is, in such a fuel tank with a sub-tank, the fuel tank and the sub-tank are communicated with each other through a communication port, and inside the sub-tank there is an inlet of a suction pipe for fuel supply and an outlet of a return pipe for returning fuel. is opened, the pump sucks the fuel in the sub-tank from the suction pipe through the filter, the required amount of fuel is injected into the engine from the fuel injection device, and the remaining fuel is returned to the sub-tank from the return pipe. It is designed to be sent back inside and circulated.

That is, in such a fuel supply system, while the fuel is circulating between the subtank and the engine, the temperature of the fuel increases due to heat received from the engine, etc., and as a result, low boiling point fractions are removed and vapor is reduced. In addition to preventing this from occurring, fresh fuel corresponding to the amount of fuel consumed by the engine is replenished into the fuel tank.

By the way, in such a fuel circulation system, the suction pipe's suction port and the return pipe's discharge port open inside the sub-tank, but in the case of a structure with a fuel injection device at the entrance to the engine, the return Since the flow rate of the fuel returned from the pipe is quite high, there was a drawback that the fuel returned from the return pipe would scatter outside the sub-tank.

In particular, if the fuel returned from the return pipe jumps out of the subtank and mixes with the fresh fuel in the main tank, the fuel sucked from the suction pipe will pass through the fuel supply port and enter the subtank. The fresh fuel that has been supplied to the tank becomes the main fuel, and the fuel that is returned from the return pipe is not directly sucked into the suction pipe. When such a situation occurs, the fuel returned from the return pipe is usually at a fairly high temperature due to heat from the engine, etc., and a large amount of the low boiling point fraction in the fuel has already been removed, causing vapor lock. Despite the fact that it has the advantage of being difficult to absorb, this advantage is hardly utilized, and the undesirable situation is that fresh fuel, which contains a considerable amount of low boiling point fractions and is prone to vapor lock, is mainly sucked into the suction pipe and circulated. It was a result.

The present invention was made to eliminate the drawbacks of the prior art, and the fuel returned from the return pipe, from which low boiling point fractions have been removed and is unlikely to cause vapor lock, is more effectively sucked into the suction pipe and returned. It is an object of the present invention to provide a subtank structure for a vehicle fuel tank that can fully utilize the advantages of fuel.

In order to achieve this purpose, the present invention
In a rectangular sub-tank with a suction pipe arranged in the center of the interior and a return pipe arranged on the side of the suction pipe with the end opening facing the side wall, the suction hole of the suction pipe and the return pipe of the sub-tank are arranged. The facing side walls, at least a part of the side wall on the return pipe side, and a part of the side wall facing the side wall on the return pipe side are each formed to be higher than the other side wall parts.

Hereinafter, details of the present invention will be explained using examples shown in the drawings.

FIGS. 1a and 1b are a sectional view and a side view showing the sub-tank structure of a vehicle fuel tank according to the present invention. The rectangular sub-tank 1 is fixed to the internal bottom wall of a main tank (not shown) by welding or the like, and the main tank and sub-tank 1 are communicated with each other through a fuel supply port (not shown). Note that since the above configuration is the same as the conventional one, further detailed explanation will be omitted.

A suction pipe 2 for supplying fuel to the engine is disposed in the center of the sub-tank 1, and a suction pipe 2 for supplying fuel to the engine is disposed on the right side of the suction pipe 2 to carry the remaining fuel not consumed by the engine to the sub-tank 1. A return pipe 3 is provided for returning the water to the interior and for further circulation. The suction hole 2A of the suction pipe 2 is opened toward the upper side wall 1A of the sub-tank 1 in FIG.
Further, the end opening of the return pipe 3, that is, the discharge port 3A is opened toward the right side wall 1B of the sub-tank 1. However, in this embodiment, among the side walls of the sub-tank 1, the upper side wall 1 facing the suction hole 2A of the suction pipe 2 is
A, the side wall on the return pipe 3 side, that is, a part 1B' of the right side wall 1B (the shaded part in FIG. 1b), and a part 1C' of the left side wall 1C facing the right side wall 1B. , each other sidewall 1
It is formed to be higher than portions B″, 1C″, and 1D.

Therefore, in this embodiment, the high-temperature fuel that is not consumed by the engine but is returned through the return pipe 3 flows from the discharge port 3A of the return pipe 3 to the right side wall 1B as shown by arrow A. Although it is injected at a fairly high speed toward the part 1B' side, it hits the part 1B', the upper side wall 1A, and the left side wall 1C' in order, causing a small swirling flow, and most of it is directly absorbed into the suction pipe 2. It will be sucked into the hole 2A. Therefore, the engine is supplied with a good fuel containing less low-boiling fractions that cause vapor lock.

In addition, in the embodiment described above, the right side wall 1
Although only the part 1B' of the right side wall 1B is made high, the same effect as in the above embodiment can be obtained even if the entire right side wall 1B is made high. However, in the side wall of the sub-tank 1, as shown in FIG. 2, not only the upper side wall 1A and the right side wall 1B,
If the left side wall 1C is also formed to be high over its entire surface, the fuel injected from the discharge port 3A of the return pipe 3 will cause a large swirling flow as shown by arrow B in the same figure, resulting in a sacrificial flow. There was a problem in that not only was the suction not drawn immediately into the suction hole 2A of the syringe pipe 2, but a portion of it also jumped out of the sub-tank 1 as shown by arrows C and D. Further, as shown in FIG. 3, the upper side wall 1A,
Even in the case where only the right side wall 1B is formed to be high over the entire surface, the fuel injected from the discharge port 3A of the return pipe 3 causes a large swirling flow as shown by the arrow E in the figure. However, there was a problem in that not only was the suction not immediately sucked into the suction hole 2A of the suction pipe 2, but part of it also jumped out of the sub-tank 1 as shown by arrows F and G. Furthermore, it is also possible to make the entire circumference of the side wall of the sub-tank 2 higher, but even in this case, since the fuel injected from the discharge part 3A of the return pipe 3 makes a large swirl, it will flow into the suction hole 2A of the suction pipe 2. The drawback was that it was not absorbed immediately. Therefore, from this, the upper side wall 1A,
In the case where at least a portion 1B' of the right side wall 1B and a portion 1C' of the left side wall 1C are formed high,
It can be seen for the first time that the purpose of this invention can be achieved.

As explained above, according to the subtank structure of the vehicle fuel tank according to the present invention, a suction pipe is disposed in the center of the interior, and a return pipe is provided on the side of the suction pipe with the end opening facing the side wall. In a rectangular sub-tank, the sub-tank has a side wall facing the suction hole of the suction pipe, at least a part of the side wall on the return pipe side, and a part of the side wall facing the side wall on the return pipe side. By forming each side wall so that it is higher than the other side wall parts, most of the fuel returned from the return pipe is immediately sucked into the suction hole of the suction pipe without scattering to the outside of the sub-tank. will be done,
Therefore, the advantages of the returned fuel can be fully utilized, and the occurrence of vapor lock caused by low-boiling fractions can be extremely effectively prevented.

[Brief explanation of the drawing]

1A and 1B are a cross-sectional view and a side view of a sub-tank structure of a vehicle fuel tank according to the present invention, and FIGS. 2 and 3 are cross-sectional views showing an example of the sub-tank structure, respectively. 1... Sub tank, 1A... Upper side wall, 1B...
...Right side wall, 1B'...part, 1C...left side wall,
1C'...part, 2...suction pipe, 2A
...Suction hole, 3...Return pipe, 3A...Discharge port.

Claims (1)

[Scope of utility model registration request] In a rectangular sub-tank with a suction pipe arranged in the center of the interior and a return pipe arranged on the side of the suction pipe with the end opening facing the side wall, the suction hole of the suction pipe and the return pipe of the sub-tank are arranged. A vehicle characterized in that facing side walls, at least a part of the side wall on the return pipe side, and a part of the side wall facing the side wall on the return pipe side are each formed to be higher than other parts of the side wall. Sub-tank structure of fuel tank.