JPH06286482A - Fuel tank - Google Patents

Abstract

PURPOSE:To restrict the generation of evaporative emission by reducing contact of a liquid phase and a vapor phase even in the case where the cross sectional area of a fuel tank is changed in the vertical direction. CONSTITUTION:A fuel tank 1 has plural granular material 2, which has a specific gravity smaller than that of the fuel and which is formed into spherical shape or polyhedron, inside thereof. Consequently, at least one part of the surface of the fuel is coated with the granular material to reduce the contact area of the vapor phase and the liquid phase, and the generation of the evaporative emission is therefor restricted regardless of a liquid level of the fuel.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automobile fuel tank, and more particularly to a fuel tank capable of suppressing the amount of vaporized gas generated.

[0002]

2. Description of the Related Art Although fuel vaporizes from a fuel tank for storing fuel for automobiles and vaporized gas is generated, it is dangerous to discharge vaporized gas to the outside as it is dangerous. Purging into the intake pipe is common. However, since the evaporated gas purged in the intake pipe becomes a disturbance to the internal combustion engine, in order to ensure smooth operation of the internal combustion engine and minimize the processing capacity of the canister, the amount of evaporated gas generated in the fuel tank must be reduced. It goes without saying that it is essentially necessary to reduce

In order to solve this problem, it is possible to increase the internal pressure of the fuel tank, but it is necessary not only to increase the design pressure resistance of the fuel tank, but also to increase the internal pressure when the cap is removed for refueling. The amount of evaporative emission is suddenly reduced and the vaporized gas is exhausted from the fuel supply port to the outside at one time, which rather impairs safety. Therefore, it has been proposed to dispose a plate-like float inside the fuel tank in order to suppress the amount of evaporative gas (for example, “Toyota Technology Publication 2184”).
(Published July 29, 1987) ").

In the fuel tank according to the present proposal, the area in which the liquid phase contacts the gas phase is reduced by the plate-like float to suppress the generation of evaporative gas. FIG. 4 is a vertical sectional view of a conventionally proposed fuel tank, in which a plate-shaped float 41 is biased downward by a spring 42. Since the float 41 is made of a material having a specific gravity smaller than that of the fuel, the float 41 becomes a state in which the liquid surface of the fuel is covered, and the contact between the liquid phase and the gas phase is blocked, so that the generation of evaporative gas can be suppressed. is there.

[0005]

However, in the fuel tank according to the present proposal, when the cross-sectional area of the fuel tank changes in the vertical direction, the contact area between the liquid phase and the gas phase is sufficient. In some cases it could not be reduced. That is, as shown in FIG. 4, since the float 41 is a single rigid body, the movement in the left, right, up, and down directions in the fuel tank is restricted, and especially when the fuel tank is full of fuel, the float 41 is above the float 41. Since there may be fuel present in the fuel, evaporation of the fuel cannot be suppressed.

The present invention has been made in view of the above problems, and reduces the contact between the liquid phase and the gas phase even when the cross-sectional area of the fuel tank changes in the vertical direction, and suppresses the generation of evaporative gas. It is an object of the present invention to provide a fuel tank that can be used.

[0007]

A fuel tank according to the present invention has a plurality of granular substances having a specific gravity smaller than that of the fuel stored in the fuel tank, inside the fuel tank.

[0008]

In the fuel tank according to the present invention, even if the cross-sectional area of the fuel tank changes in the vertical direction, a plurality of granular materials can freely change their positions and at least a part of the fuel surface is granular. The substance covers and reduces the contact area between the liquid phase and the gas phase.

[0009]

1 is a longitudinal sectional view of an embodiment of a fuel tank according to the present invention, in which a granular material 2 is provided inside a fuel tank 1.
Is stored. The granular material 2 is a spherical or polyhedral body that is made lighter than the fuel stored in the fuel tank 1 by a material that does not melt into the fuel, and is made of, for example, a solid ternary fluororesin or a hollow metal.

The particulate matter 2 floats on the fuel and is stored in such a quantity that it covers at least one layer of the maximum fuel surface of the fuel tank 1. FIG. 2 is a vertical cross-sectional view of the case where the fuel is stored in the fuel tank 1 fully. Since the surface area of the fuel is small, the particulate matter 2 is in a state of overlapping in a plurality of layers. If the number of the particulate matter 2 is increased so that two or more layers of the particulate matter 2 overlap each other even at the liquid level that provides the maximum fuel surface area, it is possible to further suppress the generation of evaporative gas.

FIG. 3 is an explanatory view of an overlapping state of the granular substances 2 when the granular substances 2 are two or more kinds of substances having different diameters, and a small diameter is provided in a gap between the granular substances 21 having a large diameter. It is possible to make the cutoff between the liquid phase and the gas phase more reliable by allowing the particulate matter 22 having the intrusion.

[0012]

According to the fuel tank of the present invention, even if the cross-sectional area of the fuel tank changes in the vertical direction, at least a part of the fuel surface is covered with the particulate matter regardless of the liquid level of the fuel. As a result, the contact area between the liquid phase and the gas phase is reduced, and the generation of evaporative gas is suppressed.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an embodiment of a fuel tank according to the present invention.

FIG. 2 is a vertical cross-sectional view (when the fuel is full) of an embodiment of a fuel tank according to the present invention.

FIG. 3 is an explanatory diagram of an overlapping state of granular materials.

FIG. 4 is a vertical cross-sectional view of a conventionally proposed fuel tank.

[Explanation of symbols]

 1 ... Fuel tank 2 ... Granular substance

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[Procedure amendment]

[Submission date] April 20, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction content]

[0009]

1 is a longitudinal sectional view of an embodiment of a fuel tank according to the present invention, in which a granular material 2 is provided inside a fuel tank 1.
Is stored. The granular material 2 is a spherical or polyhedral body that is made lighter than the fuel stored in the fuel tank 1 with a material that does not melt into the fuel, and is made of, for example, a hollow ternary fluororesin or a hollow metal.

Claims (1)

[Claims] 1. A fuel tank having a plurality of granular substances having a specific gravity smaller than that of the fuel stored in the fuel tank, inside the fuel tank.