JPH081952Y2 - Fuel tank for automobile - Google Patents

Description

[Detailed description of the device] [Industrial applications]

 The present invention relates to a fuel tank for automobiles.

[Prior art]

As a fuel tank for automobiles, a bathtub type chamber 1 having an open top surface as described in Japanese Utility Model Laid-Open No. 62-161020 is built in, and one end of a fuel feed pipe 2 and one end of a return pipe 3 are inserted therein. However, it is generally known in the past (see FIG. 4).

[Problems to be solved by the device]

By the way, in such a conventional vehicle fuel tank, return fuel returned to the inside of the chamber 1 by the return pipe 3 flows out of the chamber 1 to agitate the fuel in the fuel tank 1 and much fuel evaporative emission occurs. There was a problem of becoming. Therefore, an object of the present invention is to provide an automobile fuel tank capable of reducing the amount of fuel evaporative emission generated by the inflow of return fuel and preventing the fuel evaporative emission from flowing into the feed pipe as much as possible. To do.

To this end, the present invention relates to a vehicle fuel tank having a chamber into which one end of a fuel feed pipe and one end of a return pipe are inserted, and the chamber has a box shape. A return fuel flow passage whose opening cross-sectional area gradually increases from the inlet side to the outlet side is formed in the interior thereof, and the upper wall of the chamber is
A plurality of air vent holes are provided along the flow path of the return fuel so as to communicate with the flow path.

[Action]

In an automobile fuel tank that employs such a means,
The return fuel returned from the return pipe flows into the inlet side of the flow channel defined in the chamber and gradually decreases the flow velocity in the process of passing through the flow channel toward the outlet side of the return fuel. The evaporated gas reaches the inside of the chamber in a state of being sequentially discharged from the chamber through a plurality of air vent holes formed on the upper wall of the chamber along the flow path, and is sucked into the feed pipe from the inside of the chamber again.

【Example】

An embodiment of the present invention will be specifically described below with reference to the drawings. In FIG. 1, reference numeral 4 is a fuel tank main body, which is installed on the bottom wall 4a and has a chamber 5 built therein. The chamber 5 has a box shape having an arched planar shape in which one side of a substantially square shape is curved in a semicircular shape and swells, and a guide plate 6 arranged along the side wall 5a is provided inside the chamber 5 to flow the return fuel. The road 7 is sectioned. The flow path 7 is an insertion port 5b provided at the lower corner of the chamber 5.
Is turned in a U-turn shape from the inlet side communicating with the chamber toward the outlet side opening in the chamber 5, and the opening cross-sectional area thereof is gradually increased from the inlet side to the outlet side (the first side). (See Figures 2 and 3). A plurality of air vent holes 5d are formed in the upper wall 5c of the chamber 5 along the flow path 7. And chamber 5
One end of the fuel return pipe 8 is inserted into the insertion port 5b of the above, and one end of the feed pipe 9 penetrates through the central portion of the upper wall 5c. In the above configuration, the return fuel from the return pipe 8 flows into the inlet side of the flow path 7 together with the fuel in the fuel tank main body 4, and the flow velocity gradually increases in the process of passing through the flow path 7 toward the outlet side thereof. While falling, it reaches the inside of the chamber 5, and is again sucked into the feed pipe 9 from the inside of the chamber 5. In this way, the return fuel is returned to the box-shaped chamber 5 while gradually decreasing the flow velocity, so that the fuel in the fuel tank is rarely agitated to generate the fuel evaporative gas, and the flow rate of the flow is reduced. The fuel evaporative gas in the passage 7 is sequentially discharged to the outside of the chamber 5 through the plurality of air vent holes 5d formed in the upper wall 5c of the chamber 5 along the passage 7. Almost no fuel evaporative gas flows into the inserted chamber 5.

[Effect of device]

As described above, according to the present invention, the return fuel returned from the return pipe is returned to the box-shaped chamber 5 while gradually decreasing the flow velocity in the process of passing through the flow passage defined by the chamber. Never inadvertently stir the fuel in the fuel tank. Therefore, the amount of fuel vaporized gas generated can be reduced. Further, since the fuel evaporative gas in the flow path is sequentially discharged out of the chamber through a plurality of air vent holes formed in the upper wall of the chamber along the flow path, in the chamber where one end of the feed pipe is inserted. Almost no fuel evaporative gas flows into the chamber. Therefore, the fuel evaporative gas can be prevented from flowing into the feed pipe as much as possible.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view showing an embodiment of the present invention, FIG. 2 is a plan view of a chamber, FIG. 3 is a front view of the chamber, and FIG. Is. 1 ... Chamber, 2 ... Feed pipe, 3 ... Return pipe, 4 ... Fuel tank body, 5 ... Chamber, 5a
...... Side wall, 5b …… Insertion port, 5c …… Upper wall, 5d …… Air vent hole, 6 …… Guide plate, 7 …… Flow path, 8 …… Return pipe, 9 …… Feed pipe.

Claims (1)

[Scope of utility model registration request] 1. A fuel tank for an automobile, comprising a chamber into which one end of a fuel feed pipe and one end of a return pipe are respectively inserted, wherein the chamber has a box shape, and an opening cross-sectional area is provided in the interior from an inlet side to an outlet side. The flow passage of the return fuel that gradually increases toward the side is defined and formed, and the upper wall of the chamber is provided with a plurality of air vent holes communicating with the flow passage of the return fuel. A characteristic fuel tank for automobiles.