JPH075028B2 - Fuel suction device for fuel tank - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a fuel suction device for a fuel tank mounted on a vehicle such as an automobile.

2. Description of the Related Art Among fuel tanks for automobiles, for example
As disclosed in the publication, for the structural reason of the portion where the fuel tank is mounted, a bulging portion is formed inward on the bottom wall of the tank main body, and the bulging portion is used. It is known to avoid interference between the bottom wall of the tank body and the functional parts of the vehicle body.

Problems to be Solved by the Invention By forming the bulging portion on the bottom wall of the tank main body, the main chamber and the sub chamber are separated from each other in the substantially lower half of the tank main body. In order to prevent fuel from remaining in either one of the above, the feed pipe is branched from the middle into the main chamber side pipe and the sub chamber side pipe through the switching valve, and when the fuel in the main chamber is consumed, the switching valve is turned on. It is necessary to operate so that the fuel in the sub chamber is supplied. Therefore, not only a switching valve is required, but also a liquid level detecting device is required for each of the main chamber and the sub chamber in order to automatically switch the switching valve, and a control unit is required. It has been pointed out that it is expensive.

Therefore, the present invention provides a fuel suction device for a fuel tank that can efficiently supply fuel in the main chamber and the sub chamber without requiring a dedicated part such as a switching valve or an operation control unit thereof. is there.

Means for Solving the Problems In a structure in which a bulging portion is formed on a bottom wall of a tank main body, and a main chamber and a sub chamber are separated from each other in a substantially lower half portion of the tank main body, in the vicinity of the bottom of the main chamber A suction pipe of the feed pipe is arranged in the tank body, and an ejector is formed at the end of the return pipe projecting to the main chamber side in the tank body, while a suction pipe having the suction port arranged in the vicinity of the bottom of the auxiliary chamber is attached to the ejector. A fuel reservoir is formed in communication with the chamber and in the middle of the fuel outflow pipe of the ejector.

When the feed pump is driven, the fuel in the main chamber is sucked from the suction port of the feed pipe and supplied to the fuel supply device, and the surplus fuel is returned to the tank main body through the return pipe. The surplus fuel returned from the return pipe is vigorously ejected from the nozzle at the ejector portion by the discharge pressure of the feed pump and flows out to the fuel outflow pipe. By jetting fuel from this nozzle,
While negative pressure is generated in the chamber of the ejector, the fuel temporarily stays in the fuel pool of the fuel outflow pipe. Therefore, the displacement of the air from the opening of the fuel outflow pipe into the chamber is avoided, the decrease of the negative pressure value in the chamber is suppressed, and the fuel in the subchamber is transferred through the suction pipe to the chamber. The fuel is sucked in and is fed into the main chamber through the fuel outflow pipe together with the fuel ejected from the nozzle.

Embodiment Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

In FIGS. 1 and 2, reference numeral 1 denotes a tank main body, and a bulging portion 2 is formed inwardly at a substantially central portion of a bottom wall of the tank main body.
A main chamber 3 and a sub chamber 4 are separated from each other in a substantially lower half portion of the tank body 1. A suction port of a feed pipe 5 is arranged near the bottom of the main chamber 3, and a fuel pump (not shown) arranged outside the tank main body 1 drives the fuel in the tank main body 1 from the main chamber 3 side. It is designed so that it can be sucked and delivered to a fuel supply device (not shown). A return pipe 6 is arranged so as to project through the upper wall of the tank body 1 on the main chamber 3 side, and excess fuel not consumed by the fuel supply device is returned to the inside of the tank body 1 via the return pipe 6. It is becoming like this.

An ejector 7 is formed at the projecting end of the return pipe 6 inside the tank body 1. In this ejector 7, a nozzle 9 formed at an end of the return pipe 6 is provided in a chamber 8 provided at an end portion of the return pipe 6 in proximity to a narrowed portion 11 of a connecting portion of the chamber 8 and the fuel outflow pipe 10. The suction pipe 12 is connected to the communication port 8a formed in the chamber 8. The suction port of the suction pipe 12 is arranged near the bottom of the sub chamber 4.
A fuel reservoir 13 is formed in the fuel outflow pipe 10 of the ejector 7. In this embodiment, a check valve is closed in the fuel outflow pipe 10 by a set spring 15.
A fuel reservoir 13 is formed by providing 14 and the valve is opened by the fuel discharge pressure of the ejector 7.

According to the apparatus of the above embodiment, when the feed pump (not shown) is driven, the fuel in the main chamber 3 is fed to the fuel supply device (not shown) by the feed pipe 5. In this fuel supply device, not all of the fuel fed from the feed pipe 5 is consumed, but surplus fuel is returned to the tank body 1 via the litter pipe 6 and the tank body.

Here, since the ejector 7 is formed at the end of the return pipe 6, the fuel is ejected vigorously from the nozzle 9 toward the throttle portion 11 due to the discharge pressure of the feed pump at the ejector 7 portion. By jetting fuel from the nozzle 9,
Negative pressure is generated in the chamber 8, and the negative pressure causes the fuel in the sub chamber 4 to be sucked into the chamber 8 through the suction pipe 12, and at the same time, the jet from the nozzle 9 and the throttle 11
Then, the flow velocity is increased, the fuel flows down through the fuel outflow pipe 10, and the fuel temporarily stays in the fuel reservoir 13, passes through the check valve 14, and is fed into the main chamber 3.

Here, when the feed pump is started as described above in the state where the fuel outflow pipe 10 is submerged below the fuel level in the main chamber 3, the fuel in the sub chamber 4 is generated by the ejector action in the ejector 7 described above. After being transferred into the main chamber 3, the fuel transfer operation continues due to the synergy of the siphon effect. Due to this fuel transfer action, even if the feed pump is stopped in a state where the fuel level in the sub chamber 4 is lower than the fuel level in the main chamber 3, the check valve 14 is closed and the sif-on is performed. The backflow of fuel from the main chamber 3 to the sub chamber 4 due to the action is prevented.

When the feed pump is started in a state where the fuel level in the main chamber 3 is lower than the end of the fuel outflow pipe 10, the fuel ejected from the nozzle 9 at this start is temporarily stored in the fuel reservoir 13 as described above. Therefore, the negative pressure generated in the chamber 8 and the air from the lower end of the fuel outflow pipe 10 are not replaced with each other because the fuel reservoir 13 is filled with the fuel and is filled with the fuel.
Therefore, the negative pressure generated in the chamber 8 is not diluted, and the fuel transfer action from the sub chamber 4 to the main chamber 3 is performed satisfactorily immediately after the feed pump is started.

All of the embodiments shown in FIGS. 3 to 5 are fuel outflow pipes 10.
In addition, an orifice 16 having a much smaller passage cross-sectional area than that of the throttle 11 immediately after the nozzle 9 is provided to form the fuel reservoir 13.

In the embodiment shown in FIG. 3, the lower end opening of the fuel outflow pipe 10 is squeezed to form an orifice 16. However, as shown in FIG. It may be squeezed to form the orifice 16. Further, instead of forming the orifice 16 by subjecting the fuel outflow pipe 10 itself to compression molding as described above, as shown in FIG.
It is also possible to alternately arrange a plurality of paticle plates 17 therein to form the orifice 16 and meander the flow path to obtain a desired flow resistance.

In these embodiments, the fuel can be automatically transferred from the sub-chamber 4 to the main chamber 3 by the ejector action in the ejector 7 part, and the fuel is temporarily retained in the fuel reservoir 13 so that the chamber is changed. Negative pressure generated in 8 and fuel outflow pipe
10 The fact that the replacement action with air from the lower end can be avoided is the same as in the above-mentioned embodiment.

On the other hand, the above-described fuel transfer action is performed with the fuel outflow pipe 10 submerged below the fuel level in the main chamber 3, and the fuel level in the main chamber 3 becomes higher than that in the sub-chamber 4. If the drive of the feed pump is stopped while the fuel is out, there is no check valve in any of the fuel outflow pipes 10, but since the required flow resistance is obtained by the orifice 16 of the fuel outflow pipe 10, the main chamber due to the siphon action is obtained. The backflow of fuel from 3 to the sub-chamber 4 is prevented.

In the embodiment shown in FIGS. 6 and 7, the fuel outflow pipe 10 is arranged above the main chamber 3. In this embodiment, the fuel outflow pipe
An intermediate portion of 10 is once bent upward, and a fuel reservoir 13 is formed at the bent portion. Also this fuel spill pipe
The open end of 10 is arranged close to the side wall surface of the tank body 1,
The outflowing fuel travels along the wall surface of the tank body 1 and flows down into the main chamber 3.

According to this embodiment, the fuel ejected from the nozzle 9 is temporarily retained in the fuel reservoir 13 at the time of starting the feed pump, and the fuel reservoir 13 is filled with the fuel. It is possible to favorably perform the fuel transfer action from the sub chamber 4 to the main chamber 3 immediately after the feed pump is started, without the action of replacing the negative pressure with the air from the lower end of the fuel outflow pipe 10.

Further, the fuel flowing out from the fuel outflow pipe 10 travels along the side wall surface of the tank body 1 and flows down into the main chamber 3, so that the main chamber 3
The fuel does not bubble inside and the feed pipe 5
It does not interfere with the fuel supply by sucking bubbles.

Regarding the formation of the fuel reservoir 13, other than the above, although not shown, the intermediate portion of the fuel outflow pipe 10 may be formed by twisting it upward.

8 and 9 show that the fuel outflow pipe 10 is divided into an upstream pipe 10A and a downstream pipe 10B, and these upstream pipe 10A and downstream pipe 10 are divided.
B and B are connected to each other via a fuel reservoir 13 composed of a casing. The upper and lower pipes 10A and 10B are connected to the fuel reservoir 13
Inside, the end portions are offset in the horizontal direction, and are lapped in the vertical direction so as to project. Further, the fuel reservoir 13 has an air vent hole 18 on the upper wall, and when the fuel in the sub chamber becomes small and air is sucked together with the fuel from the suction pipe 12 and the fuel bubbles in the fuel reservoir 13, Air vent hole
It is designed to function as a separator by removing air from 18. In addition, a small hole 19 for drain is formed in the bottom wall of the fuel reservoir 13.

According to the device of this embodiment, the fuel flowing out from the upstream pipe 10A temporarily stays in the fuel reservoir 13 and the downstream pipe 10B
Flows out into the main chamber 3 via. Therefore, at the time of starting the feed pump, the ejector 7 is operated in the same manner as in the above-mentioned respective embodiments.
It is possible to prevent the negative pressure generated in the chamber 8 from being replaced with air from the lower end of the fuel outflow pipe 10 (downstream pipe 10B in this embodiment). Further, when the feed pump is stopped, the fuel staying in the fuel reservoir 13 is drained from the drain small hole 19, so that the backflow of the fuel from the main chamber 3 to the sub chamber 4 due to the siphon action can be prevented.

As described above, according to the present invention, by driving the feed pump, the fuel in the main chamber is discharged to the fuel supply device, and at the same time, the ejector action in the ejector portion formed at the end of the return pipe causes The fuel can be smoothly transferred into the main chamber, and since it does not require a dedicated electric part as in the conventional case, it is structurally simple and a significant cost reduction can be realized. . In addition, since the fuel pool is formed in the middle of the fuel outflow pipe of the ejector, even if the fuel pump is started when the fuel level in the main chamber is lower than the lower end of the fuel outflow pipe, it will flow out from the ejector nozzle. Since the fuel to be stored temporarily fills the fuel reservoir, the negative pressure generated in the chamber of the ejector and the air from the lower end of the fuel outflow pipe do not replace each other. There is a practically great effect that a smooth fuel transfer action can be performed immediately after the feed pump is started without diluting the generated negative pressure.

[Brief description of drawings]

FIG. 1 is a schematic sectional explanatory view showing a first embodiment of the present invention,
FIG. 2 is an enlarged view of the main part, and FIGS. 3, 4, and 5 are sectional views showing the main parts of the second, third, and fourth embodiments of the present invention. FIG. 6 is a schematic cross-sectional explanatory view showing a fifth embodiment of the present invention, FIG. 7 is an enlarged view of the essential part thereof, and FIG. 8 is a schematic cross-sectional explanatory view showing the sixth embodiment of the present invention. FIG. 9 is an enlarged view of the main part. 1 ... Tank body, 2 ... Swelling part, 3 ... Main chamber, 4 ...
Sub-chamber, 5 ... Feed pipe, 6 ... Return pipe,
7 ... Ejector, 8 ... Chamber, 9 ... Nozzle, 10 ...
… Fuel outflow pipe, 12 …… Suction pipe, 13 …… Fuel pool.

Claims (1)

[Claims] 1. A structure in which a bulging portion is formed on a bottom wall of a tank main body and a main chamber and a sub chamber are separated from each other in a substantially lower half portion of the tank main body, and a feed pipe is provided near a bottom portion of the main chamber. A suction pipe is arranged and an ejector is formed at the end of the return pipe projecting to the main chamber side in the tank body, while a suction pipe with the suction port arranged near the bottom of the sub chamber communicates with the chamber of the ejector. A fuel suction device for a fuel tank, wherein a fuel reservoir is formed in the middle of the fuel outflow pipe of the ejector.