GB2414455A

GB2414455A - Vehicle fuel tank

Info

Publication number: GB2414455A
Application number: GB0510606A
Authority: GB
Inventors: Kunio Miyauchi
Original assignee: Honda Motor Co Ltd
Current assignee: Honda Motor Co Ltd
Priority date: 2004-05-24
Filing date: 2005-05-24
Publication date: 2005-11-30
Anticipated expiration: 2025-05-24
Also published as: GB2414455B; TW200607672A; DE102005023713B4; CN1701982A; JP2005335436A; TWI274679B; GB0510606D0; CN100360334C; JP4065252B2; DE102005023713A1

Abstract

By fusion welding joining surfaces 22 at distal ends of protruding portions 12a, 13a which are made to protrude, respectively, from an upper wall 12 and a lower wall 13 of a tank main body 11, the protruding portions 12a, 13a can not only increase the rigidity of the tank main body 11 but also function as baffle plates for preventing the movement of fuel therein. In addition, a passageway 23 is formed along the joining surfaces 22 at the distal ends of the protruding portions 12a, 13a in such a manner as to allow the passage of fuel, and the passageway 23 so formed can not only prevent a violent rebound of fuel that collides against the protruding portions 12a, 13a to thereby enhance further the baffle plate effect but also implement a smooth vapor-liquid separation within the tank main body 11. Moreover, since the passageway 23 is formed along the joining surfaces 22 at the distal ends of the protruding portions 12a, 13a, the formation of the passageway 23 is eased to an extreme extent.

Description

24 1 4455

VEHICLE FVEL TANK

The present invention relates to a vehicle fuel tank comprising a protruding portion formed on at least one of pert of an upper wall and part of a lower wall of a tank main body in such a manner as to protrude therefrom towards the other of the part of the upper wall and the part of the lower wall, whereby the part of the upper wall and the part of the lower wall are joined to each other at a joining surface at a distal end of the protruding portion.

When the surface of fuel in a fuel tank undergoes large fluctuations or small undulations due to the acceleration or oscillation of a vehicle which occurs while the vehicle is driven, there are problems in that the suction of fuel becomes difficult or that a collision noise is generated by fuel which collides with an internal surface of the fuel tank. To cope with them, there is known in Japanese Utility Model Publication No. Hei. 7-97219 (hereinafter referred as patent document No. 1) below a fuel tank in which a baffle plate is welded to a lower wall thereof to restrict the movement of fuel therein.

26 In addition, there is proposed a synthetic resin fuel tank in which distal ends of protruding portions which protrude from an upper wall and a lower wall of the fuel tank in such a manner as to approach each other are welded together so not only that the rigidity of the upper wall and lower wall of the fuel tank is increased but also that the protruding portions are allowed to function as a baffle plate.

Incidentally, the baffle plate described in the patent document No. 1 is fixed to the lower wall of the fuel tank and there is provided a gap between an upper end of the baffle plate and the upper wall of the fuel tank. In a case where the baffle plate is formed by welding together the distal ends of the protruding portions which protrude from the upper wall and the lower wall of the fuel tank in such a manner as to approach each other, however, there is caused the following problem. That is, since the upper wall and the lower wall are joined to each other altogether so that the aforesaid gap cannot be formed, when caused to move within the fuel tank, fuel collides against the baffle plate and then rebounds strongly, causing problems that the effect of the baffle plate to suppress the violent surface undulation of fuel in the fuel tank is reduced and that the vapor-liquid separation cannot be performed smoothly within the fuel tank.

An object of at least the preferred embodiments of the present invention is to improve the rigidity of a tank main body of a fuel tank while allowing the effect to prevent the surface undulation of fuel to be exhibited.

According to a first aspect of the invention, there is proposed a vehicle fueltank comprising a protruding portion formed on at least one of pert of an upper wall and part of a lower wall of a tank main body in such a manner as to protrude therefrom towards the other of the part of the upper wall and the part of the lower wall, whereby the upper wall and the lower wall are joined to each other at a joining surface at a distal end of the protruding portion, wherein a passageway is formed along the joining surface which allows the passage of fuel therethrough.

According to a second aspect of the invention, there is proposed a vehicle fueltankas set forthin the first aspect of the invention, wherein the passageway has a smoothly curved wall portion.

According to a third aspect of the invention, there is proposed a vehicle fuel tank as seL forth in the first aspect oftheinvention, wherein one side of the passagewayis opened.

According to the first aspect of the invention, the upper wall and the lower wall are joined to each other at the joining surface at the distal end of the protruding portion which is formed on atleastone of the part of the upper wall and the part of the lower wall of the tank main body in such a manner as to protrude towards the other of the part of the upper wall and the part of the lower wall. Therefore, the protruding portion is allowed not only to increase the rigidity of the tank main body but also to function es a baffle plate for preventing the movement of fuel in the fuel tank.

In addition, since the passageway is formed along the joining surface at the distal end of the protruding portion which allows the passage of fuel therethrough, the strong rebound of fuel which collides against the protruding portion is prevented by this passageway, thereby making it possible not only to increase further the baffle plate effect but also to carry out a smooth vapor-liquid separation within the tank main body. Moreover, since the passageway is formed along the joining surface et the distalendof the protruding portion, the passageway can be formed extremely easily.

According to the second aspect of the invention, since the passageway formed along the joining surface where the upper wall and the lower wall of the tank main body are joined together has the smoothly curved wall portion, it is possible to prevent the generation of cracking and/or separation in the joining surface due to the concentration of stress onto the wall portion of the passageway.

According to the third aspect of the invention, since the side of the passageway formed along the joining surface where the upper wall and the lower wall of the tank main body are joined together is opened, fuel that is brought into collision with the passageway in a transverse direction is allowed to escape into the interior of the passageway which is opened on the side thereof, whereby the rebound of fuel is suppressed, thereby making it possible to enhance further the effect to prevent the surface undulation of fuel (herein after referred as the fuel surface undulation preventive effect).

Certain preferred embodiments will now be described, by way of example only and with reference to the accompanying drawings, in which: Fig. 1 is a perspective view of a vehicle fuel tank according to a first embodiment of the invention.

Fig. 2 is a sectional view taken along the line 2-2 in Fig. Fig. 3 is a sectional view taken along the line 3-3 in Fig. 1.

Fig. 4 is a view corresponding to Pig. 3, which illustrates a vehicle fuel tank according to a second embodinet.

Fig. 5 is a view corresponding to Fig. 3, which illustrates a vehicle fuel tank according to a third embodiment.

Fig. 6 is a view corresponding to Fig. 3, which illustrates a vehicle fuel tank according to a fourth 26 embodiment.

Figs. 1 to 3 are such as to show a first embodiment, in which Fig. 1 is a perspective view of a vehicle fuel tank, Fig. 2 is a sectional view taken along the line 2-2 in Fig. 1, and Fig. 3 is a sectional view taken along the line 3-3 in Fig. 1.

A tank main body 11 of a vehicle fuel tank T has an upper wall 12 and a lower wall 13 and is molded from a synthetic resin. A fuel pump unit 17 is supported via a stay 16 on a lower surface of a mount flange 15. The mount flange 15 detachably covers an opening 19 formed in the upper wall 12 of the tank main body 11. A feed pipe 18, which extends from the fuel pump unit 17, penetrates the mount flange IS to thereby be connected to an engine (not shown). A return pipe 19 from the engine penetrates the mount flange 15 to thereby extend into the fuel tank T. In addition, a liquid level se,nsor 21 having a float 20 is provided on the lower surface of the mount flange 15.

A dumb-bell protruding portion 12a protrudes downwards from the upper wall 12 towards the lower wall 13 of the tank main body 11. A dumb-bell protruding portion 13a protrudes upwards from the lower wall 13 towards the upper wall l2 of the tankmainbodyl]. The dumb-bell protruding portlonsl2a, 13a are fusion welded together at substantially rectangular joining surfaces 22. A passageway 23 penetrates across the joining surfaces 22 at alongitudinal central portion "hereof.

A wallportion 23a of the passageway23 is formed into a smooth circle or oval so as to avoid stress concentration. The formation of the passageway 23 is facilitated by making use of the joining surfaces 22 of the protruding portions 12, 13 to form the passageway 23.

The protruding portions 12a, 13a are provided so as to extend in a transverse direction (a direction indicated by arrows a-a in Fig. 1) of the tank main body 11. A primary compartment 24 and a secondary compartment 25 are defined in the interior of the tank main body 11 in such a manner as to be separated apart from each other across the protruding portions12a, 13a in a longitudinal direction of the tank main body 11 (a direction indicated by arrows b-b in Fig. 1) of the tank main body 11. However, the primary compartment 24 and the secondary compartment 25 are not separated from each other in a complete fashion but are made to communicate with each other via interior portions of the tank main body which are situated transversely outwards of longitudinal end portions of the protruding portions 12a, 13a and the passageway 23. As this occurs, it is preferable that the height h of the passageway 23 is made to be 909 or smaller than the height H of the tank main body 11 (h/H< 409).

Next, the function of the first embodiment, which is constructed as has been described heretofore, will be described.

When the internal pressure of the tank main body 11 fluctuates due to changes in temperature, the upper wall 12 and the lower wall 13, which are flat and wide in area, tend to deform in a vertical direction. However, in the present invention, a rigidity which can bear the fluctuation in the internal pressure can be imparted to the tank main body 11 by fusion welding the protruding portion 12a of the upper wall 12 and the protruding portion 13a of the lower wall 13 together at the joining surfaces 22.

In addition, when fuel in the tank main body 11 attempts to move in the longitudinal direction (the direction indicated by the arrows b-b in Fig. 1) in association with the acceleration or oscillation of the vehicle which occurs while the vehicle is driven, the protruding portions 12a, 13a, which are interposed between the primary compartment 24 and the secondary compartment 25, function as baffle plates to thereby prevent the movement of the fuel. Therefore, not only a large fluctuation of the fuel level can be suppressed but also the generation of noise can be prevented which would otherwise occur due to a violent collision of the fuel against an internal surface of the tank main body 11.

As this occurs, since the passageway 23 is formed in the central portions of the protruding portions 12a, 13a in such a manner as to establish a communication between the primary compartment 24 and the secondary compartment 25, part of fuel which collides against the protruding portions 12a, 13a passes through the passageway 23. Therefore, the amount of fuel which is caused to rebound on the protruding portions 12a, 13a is reduced, so that the surface undulation of fuel can be suppressed more effectively, and the function of the protruding portions 12a, 13a as the baffle plates is improved further. In addition, in the event that a large quantity of air penetrates into, for example, the secondary compartment due to the fluctuation of the fuel level, the air, which has so penetrated, can be returned to the primary compartment 29 via the passageway 23 without no delay. Therefore, the vapor-liquid separation function of the tank main body 11 can be enhanced, so that the fuel levels in the primary and secondary compartments 24, 25 can be made uniform.

In particular, the effect of the protruding portions 12a, 13a as the baffle plates can be exhibited sufficiently by making the height h of the passageway 23 be 90% or smaller than the height H of the tank main body 11 (h/H<901). Given h/H>90%, too much fuel easily passes through the passageway 23, whereby the fuel surface undulation preventive effect The occurrence of stress concentration, which would be caused in case the internal pressure of the tank main body 11 is increased or an impact is applied from the outside, can be suppressed by the sufficiently curved construction of the wall portion 23a of the passageway 23, thereby making it possible to prevent the generation of cracking and/or separation in the joining surfaces 22.

Next, a second embodiment of the invention will be described based on Fig. 4.

The second embodiment is such that a side of a wall portion 23a of a passageway 23 is opened, and the other constituent features remain the same as those of the first embodiment. According to the second embodiment, when fuel in a tank main body 11 is caused to move in a direction indicated by an arrow c in association with the acceleration or oscillation of the vehicle when it is driven, since part of fuel is allowed to escape into primary and secondary compartments24, 25 via the passageway 23 from the opened side thereof, the rebound of fuel is reduced, thereby making it possible to suppress the surface undulation of fuel more effectively.

Next, a third embodiment of the invention will described based on Fig. 5.

The third embodiment is such that a passageway 23 is ] O formed into a shape having a dumb-bell section, in Welch the cross sectional area of the passageway can tee adjusted without increasing the height of the passageway 23.

Next, a fourth embodiment of the invention will be described based on Fig. 6.

The fourth embodiment is such that a passageway 23 is formed into a shape having a saddle-like section, in which the fuel surface undulation preventive effect can be reduced in response to an increase in fuel level.

Thus, while the embodiments of the invention have been described heretofore, the invention can be modified in various ways as to the design thereof without departing from the scope thereof.

For example, while the tank main bodies 11 in the embodiments are molded from synthetic resin, they may be formed of a metal.

In addition, while, in the embodiments, the protruding portion 12a of the upper wall 12 and the protruding portion 13a of the lower wall 13 are fusion welded together at the joining surfaces 22, other joining means can be adopted including bonding and other types of welding.

Furthermore, while, in the embodiments, the protruding portions 12a, 13a are formed on both the upper wall 12 and the lower wall 13, the protruding portion may be formed on only either of them.

Moreover, while, in the embodiments, the tank main body 11 has the single passageway 23, a plurality of passageways 23 may be provided.

In addition, the shape of the passageway 23 is not limited to those described in the embodiments but may be modified appropriately.

Claims

WHAT IS CLAIMED IS: 1. A vehicle fuel tank comprising: a tank main body

including an upper wall and a lower wall; a protruding portion formed on at least one of part of the upper wall and part of the lower wall of the tank main body in SUC}1 a manner as to protrude therefrom towards the other of the part of the upper wall and the part of the lower wall, whereby the upper wall and the lower wall are joined to each other at a joining surface at a distal end of the protruding portion; and a passageway formed along the joining surface for allowing the passage of fuel therethrough.
2. A vehicle fuel tank as set forth in Claim 1, wherein the passageway has a smoothly curved wall portion.
3. A vehicle fuel tank as set forth in Claim 1 or 2, wherein one side of the passageway is opened.
4. A vehicle fuel tank as set forth in Claim 1 or 2, wherein the passageway has a saddle-like section.
S. A vehicle fuel tank as set forth in any preceding claim, wherein a height h of the passageway and a height H of the tank main body satisfy the following equation: h/H-<4O-.
6. A fuel tank substantially as hereinbefore described, with reference to Figures 1 to 3.
7. A fuel tank substantially as hereinbefore described, with reference to Figure 4.
8. A fuel tank substantially as hereinbefore described, with reference to Figure 5.
9. A fuel tank substantially as hereinbefore described, with reference to Figure 6.