JP2645957B2 - Automotive fuel tank - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel tank for an automobile, and more particularly to a fuel tank having a vapor separator provided at a discharge port of a return tube.

[0002]

2. Description of the Related Art Generally, a fuel supply system of an automobile is configured such that fuel in a fuel tank is supplied to an engine by a fuel pump, and surplus fuel is returned to the fuel tank via a return tube. The fuel returned from the return tube into the fuel tank may include vapor generated by overheating in the engine part, particularly when the engine is restarted after stopping.

[0003] In this regard, Japanese Utility Model Laid-Open No. 60-114023 discloses a case in which a discharge port of a return tube is arranged near a suction port of a main tube connected to a suction port of a so-called in-tank type fuel pump. It has been proposed to provide a vapor separator so that fuel containing vapor is not sucked into the main tube, and to provide a vapor tube for discharging the vapor separated by the vapor separator out of the tank.

[0004]

In the fuel tank described in the above publication, the fuel pump and the vapor separator, that is, the vapor separator, are connected to the evaporator tube via the vapor tube, and the separated vapor is connected to the evaporator tube. It is configured to be adsorbed to a charcoal canister via a tube.

[0005] However, it is extremely difficult to dispose the vapor separator as described in the above publication, and it is also difficult to position the vapor separator in the tank body. Although the mounting structure of the return tube is not shown in the above publication, if it is configured to be supported by a mounting plate that covers a mounting opening formed in the tank body, it is difficult to assemble the vapor tube, It is necessary to take measures such as forming an opening in the tank body separately for assembly.

Accordingly, the present invention provides a fuel tank for a vehicle having a vapor separator provided at a discharge port of a return tube, in which the vapor separator can be easily arranged in the tank body, and the vapor tube can be appropriately and easily formed. It is intended to be able to be arranged.

[0007]

In order to achieve the above object, the present invention provides a tank body, a fuel pump for supplying fuel from the tank body to an engine, and a fuel tank for supplying surplus fuel supplied to the engine to the tank body. A return tube, and a vapor separator provided at a discharge port of the return tube, wherein the vapor separator defines a hollow portion having a predetermined capacity and has openings at both ends.
A casing having a vapor discharge port formed at one end thereof, and a vapor tube communicating with the vapor discharge port of the casing, the return tube being inserted through one opening of the casing, and The discharge port of the return tube is housed in the housing, the other opening of the housing is located near the bottom surface of the tank body, and the open end of the vapor tube is above the highest fuel level in the tank body. It is arranged so as to protrude.

In the fuel tank for an automobile, it is preferable that the vapor tube is formed of a flexible material and one end is fixed to the vapor discharge port.

In the fuel tank for an automobile, the vapor separator may be formed of a flexible material, and the vapor tube may be formed integrally with the vapor separator.

In the fuel tank for an automobile, the inner diameter of the vapor tube is preferably 1 to 5 mm.

[0011]

In the fuel tank for an automobile having the above-described structure, the vapor separator provided at the discharge port of the return tube is a casing defining a hollow portion having a predetermined capacity, and is provided through one opening of the casing. The return tube is inserted so that the discharge port is housed in the housing, and the other opening of the housing is arranged near the bottom surface of the tank body.
Further, the vapor separator includes a vapor tube communicating with a vapor discharge port formed in the housing, and is arranged such that an open end of the vapor tube protrudes above the highest fuel level in the tank body. . Further, when the vapor tube is formed of a flexible material, the vapor tube can be accommodated in the tank body while bending the vapor tube when assembling the vapor separator to the tank body.

The fuel in the tank body is supplied to the engine by the fuel pump, and surplus fuel is returned to the tank body via the return tube. In this case, since the fuel is discharged from the return tube into the vapor separator, even if the fuel contains vapor, gas-liquid separation is appropriately performed by the vapor separator. Sound insulation by the separator. In particular, when the inner diameter of the vapor tube is 1 to 5 mm, the fuel and the gas are not exchanged in the vapor tube, so that no abnormal noise is generated here.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 shows the overall structure of a fuel supply system including an automobile fuel tank according to the present invention, wherein an in-tank type fuel pump 3 contained in a tank
, A liquid fuel (hereinafter simply referred to as fuel) is supplied to the engine E. The main tube 4 is connected to a fuel injection device F via a delivery tube D for supplying and distributing fuel, and is connected to a pressure regulator R for adjusting the supply fuel pressure. The pressure regulator R is connected to a tank via a return tube 6. It is connected to the main body 2. The main tube 4 has a fuel filter 5
A pulsation damper P is provided at the inlet of the delivery tube D to attenuate the pulsation of the supply fuel pressure.

The pressure regulator R has a control port (not shown) connected to the intake pipe of the engine E, and opens and closes a fuel passage according to the intake pipe negative pressure.
Is controlled so that the pressure of the fuel injected into the intake pipe has a constant pressure difference with respect to the negative pressure of the intake pipe.
Is returned to the tank main body 2 via.

As shown in FIG. 1, a sub-tank 7 is fixed to the bottom of the tank body 2. As is well known, the sub-tank 7 communicates with the inside of the tank body 2 via a communication passage (not shown) at the bottom thereof, and is configured so that fuel flows into the sub-tank 7. The fuel pump 3 is supported by the tank body 2 via the bracket 8 such that the suction port 3b of the fuel pump 3 is located at the bottom in the sub tank 7. That is, the mounting plate 9 is fixed by screws or the like via the gasket 9a so as to close the mounting opening 2a formed in the upper part of the tank body 2, and one end of the bracket 8 is fixed to this mounting plate 9, The other end supports the fuel pump 3 via cushion rubber or the like.

The main tube 4 and the return tube 6 are provided through the mounting plate 9 and are joined by brazing or the like. The open end of the main tube 4 is connected to the discharge port 3 a of the fuel pump 3. The fuel pump 3 incorporates, for example, an impeller type pump and a DC motor for driving the same, and the structure thereof is well-known, so that the description is omitted. The suction port 3b of the fuel pump 3
Is equipped with a filter 3c.

As shown in FIG. 3, the bracket 8 is formed, for example, by bending a plated steel plate having a hat-shaped cross section into a substantially rectangular shape, and further bending one end thereof to form a flange portion 8a. The flange portion 8a is joined to the mounting plate 9 by welding or the like. The other end of the bracket 8 supports the fuel pump 3 via cushion rubber or the like. Further, an engagement portion 8b is formed on the bracket 8 on the side of the fuel pump 3. The engaging portion 8b of the present embodiment is formed by forming a circular hole 8c and a cutout 8d having a width smaller than the diameter of the hole 8c and connected to the circular hole 8c in a locking piece extending laterally from the bracket 8. The vapor separator 10 is supported between the engaging portion 8b of the bracket 8 and the tip of the return tube 6.

The vapor separator 10 of this embodiment is a casing formed as shown in FIGS. 4 to 6 by blow molding of a synthetic resin such as polyethylene. The vapor separator 10 is bent in a substantially rectangular shape when viewed from the front, and a gas-liquid separation portion 10a is formed on one side around the bent portion, and a fuel discharge portion 10b is formed on the other side. The gas-liquid separation unit 10a
A hollow portion having a predetermined capacity is formed, and an opening 11 and a vapor discharge port 13 are formed at one end. As shown in FIG.
The return tube 6 penetrates the opening 11 of the vapor separator 10, and the discharge port 6a is disposed in the hollow portion. A vapor tube 20 made of a flexible material such as rubber is attached to the vapor discharge port 13.

On the other hand, the fuel discharge portion 10b is formed in a substantially elliptical (L> W) flat cross section as shown in FIG. 7, and an opening 12 for discharging fuel is formed at an end portion. As shown in FIGS. 5 and 8, an engagement protrusion 14 having a head portion 14a having a larger diameter than the hole 8c of the engagement portion 8b and a neck portion 14b having a smaller diameter than the hole 8c of the engagement portion 8b is provided on the side wall of the fuel discharge portion 10b of the vapor separator 10. The bulge is formed.

When the vapor separator 10 is supported by the bracket 8, the return tube 6 is first inserted into the opening 11, and the neck 14b of the engaging projection 14 is engaged while sliding the vapor separator 10. It is fitted into the notch 8d of the joint 8b and pressed until the neck 14b is positioned in the hole 8c.
Thereby, both ends of the vapor separator 10 are supported by the return tube 6 and the engaging portion 8b.
The head 14a of the engaging projection 14 has a larger diameter than the hole 8c of the engaging portion 8b, so that it does not fall off. The vapor separator 10 is disposed in the sub-tank 7 of the tank main body 2 as shown in FIG. The opening is formed in a direction in which a flow is formed in the same direction.

When fuel is supplied to the tank main body 2 to the maximum extent (commonly called full tank) with the vapor tube 20 attached to the vapor separator 10, the open end of the vapor tube 20 is closed as shown in FIG. It is formed so as to protrude above the maximum fuel liquid level FLm by a height H. The value of the height H is preferably 5 to 15 mm. As a result, the vapor separated in the vapor separator 10 is not released into the fuel in the tank body 2 but is reliably discharged into the space in the tank body 2.

Further, since the vapor tube 20 is formed of a flexible material such as rubber, as shown in FIG.
When a is lower than the maximum fuel liquid level FLm, the vapor tube 20 is easily bent when the assembly including the fuel pump 3 and the vapor separator 10 shown in FIG. 3 is inserted into the tank body 2 from the mounting opening 2a. Can be inserted. Then, the vapor tube 20 is easily erected in the tank body 2 by the restoring force,
As described above, the predetermined height H is higher than the maximum fuel level FLm.
It is held in a protruding state.

The vapor separator 10 may be formed of a flexible material, and the vapor tube 20 may be formed integrally with the vapor separator 10. For example, if the base of the vapor tube 20 is formed in a bellows shape, It can be easily bent at the time of assembly.

In the fuel tank for an automobile having the above-described structure, when the fuel pump 3 operates, fuel is sucked from the inlet 3b through the filter 3c and supplied to the main tube 4 from the outlet 3a. This fuel is supplied to the engine E via the fuel filter 5 and the pulsation damper P, and returned to the tank body 2 via the return tube 6 via the pressure regulator R. Thereby, the fuel injected into the engine E is controlled to a pressure having a certain pressure difference with respect to the negative pressure of the intake pipe.

The fuel returned to the tank body 2 is discharged from the discharge port 6 a of the return tube 6 into the vapor separator 10. At this time, if the fuel in the tank body 2 is not sufficient, the fuel level FL in the sub tank 7 becomes as shown in FIG. 9, for example. Thus, in the vapor separator 10, the fuel discharged from the discharge port 6a is
a through the inner wall along the inner wall, and the opening 1 of the fuel discharge portion 10b
2 is discharged into the sub tank 7.

As described above, the fuel in the return tube 6 includes vapor generated when the fuel passes through the engine E. This vapor is separated when the fuel is discharged from the discharge port 6a, 13 to vapor tube 2
0 is discharged to the space in the tank main body 2 through the air outlet. Therefore, only the liquid fuel is discharged into the sub tank 7, and no vapor is released into the fuel in the tank body 2.

Thus, the vapor contained in the fuel in the return tube 6 is reliably separated in the vapor separator 10. In this case, abnormal noise is generated when the vapor is separated. However, since the noise is shielded by the vapor separator 10, the abnormal noise does not leak out of the tank body 2.
Further, even when the fuel is supplied until the fuel is full, the vapor tube 20 keeps the maximum fuel liquid level F as shown in FIG.
Since it is open above Lm, the vapor is reliably separated in the vapor separator 10 and is not released into the fuel in the tank body 2.

The space in the tank body 2 is communicated with a canister (not shown) via an evaporator tube (not shown) joined to the tank body 2. Thus, the vapor separated in the vapor separator 10 is adsorbed by an adsorbent such as charcoal in the canister.

FIGS. 11 to 14 are schematic views showing the relationship between the fuel and the gas in the vapor tubes 20 and 20x according to one embodiment of the present invention and the comparative example. The vapor tube 20 is formed integrally with the vapor separator 10. Are simplified. 11 and 12 correspond to one embodiment of the present invention, and the inner diameter of the vapor tube 20 is 1 to 5 m.
m. On the other hand, in the comparative example of FIGS. 13 and 14, the inner diameter of the vapor tube 20x is 6 m.
m and larger than the vapor tube 20 of FIGS. 11 and 12.

In FIG. 11, assuming that the pressure in the space inside the tank body 2 is P0 and the pressure in the space inside the vapor separator 10 is P2, the pressure difference P1 between the pressure P0 and the pressure P2 is equal to the fuel and fuel in the vapor tube 20. The inside of the vapor separator 10 is in a sealed state as shown in FIG. 11 in balance with the gas resistance.

On the other hand, in the comparative examples shown in FIGS. 13 and 14, since the inner diameter of the vapor tube 20x is large, when the amount of vapor in the fuel discharged into the vapor separator 10x increases, the fuel in the vapor tube 20x is pushed up. As shown in FIG. 14, the fuel and the bubbles (gas) are repeatedly exchanged in the vapor tube 20x, and when the bubbles are released into the space of the tank body 2, an abnormal noise (buzzing sound) is generated.
Occurs.

In one embodiment of the present invention, when the amount of vapor contained in the fuel discharged from the return tube 6 increases and the gas pressure in the vapor separator 10 increases, the fuel in the vapor tube 20 is pushed up and discharged from the tip. However, the fuel and the gas in the vapor separator 10 are not exchanged in the vapor tube 20, and only the fuel is discharged as shown in FIG. 12, and the space in the vapor separator 10 is different from the space in the tank body 2. Communicate. According to experiments,
In a general automobile fuel tank, the best result was obtained when the inner diameter of the vapor tube 20 was about 2.5 mm.

[0033]

Since the present invention is configured as described above, the following effects can be obtained. That is, in the automotive fuel tank of the present invention, the vapor separator has a predetermined capacity.
A return tube is inserted through one opening of the housing, the discharge port is housed in the housing, and the other opening of the housing is near the bottom surface of the tank body. Therefore, the vapor separator can be easily arranged in the tank body. Moreover, the vapor separator includes a vapor tube communicating with a vapor discharge port formed in the housing, and is arranged such that an open end of the vapor tube projects above the highest fuel level in the tank body. Therefore, the vapor tube can be appropriately and easily arranged. Further, since the vapor separator and the vapor tube can be made detachable, maintenance and inspection are easy.

In particular, if the vapor tube is formed of a flexible material and one end is fixed to the vapor discharge port, or if the vapor tube is formed integrally with the vapor separator by the flexible material, the production is easy. At the same time, the vapor tube can be accommodated in the tank body while being bent, and the assembling operation is easy.

Further, the inner diameter of the vapor tube is 1 to 5 m.
In the case of m, the fuel and the gas in the vapor separator are not exchanged in the vapor tube, so that generation of abnormal noise can be prevented.

[Brief description of the drawings]

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

FIG. 2 is a perspective view showing a fuel supply system including a vehicle fuel tank according to one embodiment of the present invention.

FIG. 3 is an assembled perspective view of a fuel pump and a vapor separator mounted on a bracket according to an embodiment of the present invention.

FIG. 4 is a perspective view of a vapor separator in one embodiment of the present invention.

FIG. 5 is a front view of a vapor separator in one embodiment of the present invention.

FIG. 6 is a plan view of a vapor separator in one embodiment of the present invention.

FIG. 7 is a sectional view taken along the line AA in FIG.

FIG. 8 is a sectional view taken along line BB in FIG. 6;

FIG. 9 is a longitudinal sectional view of a vapor separator in one embodiment of the present invention.

FIG. 10 is a cross-sectional view of a vapor tube mounting portion of a vapor separator according to one embodiment of the present invention.

FIG. 11 is a schematic diagram showing a relationship between fuel and gas in a vapor tube in one embodiment of the present invention.

FIG. 12 is a schematic diagram showing a relationship between fuel and gas in a vapor tube in one embodiment of the present invention.

FIG. 13 is a schematic diagram showing a relationship between fuel and gas in a vapor tube in a comparative example.

FIG. 14 is a schematic diagram showing a relationship between fuel and gas in a vapor tube in a comparative example.

[Explanation of symbols]

 2 Tank main body 2a Mounting opening 3 Fuel pump 3c Filter 4 Main tube 5 Fuel filter 6 Return tube 6a Discharge port 7 Sub tank 8 Bracket 8b Engagement section 9 Mounting plate 10 Vapor separator 10a Gas-liquid separation section 10b Fuel discharge section 11, 12 Opening 13 Vapor discharge port 14 Engagement projection 20 Vapor tube

Claims (4)

(57) [Claims] 1. A fuel tank comprising: a tank body; a fuel pump for supplying fuel from the tank body to an engine; and a return tube for returning excess fuel supplied to the engine to the tank body. In an automotive fuel tank provided with a separator, the vapor separator defines a hollow portion having a predetermined capacity and has openings at both ends.
A casing having a vapor discharge port formed at one end thereof, and a vapor tube communicating with the vapor discharge port of the casing, the return tube being inserted through one opening of the casing, and The discharge port of the return tube is housed in the housing, the other opening of the housing is located near the bottom surface of the tank body, and the open end of the vapor tube is above the highest fuel level in the tank body. A fuel tank for an automobile, wherein the fuel tank is disposed so as to protrude from the vehicle. 2. The fuel tank for an automobile according to claim 1, wherein said vapor tube is formed of a flexible material and one end is fixed to said vapor discharge port. 3. The fuel tank for an automobile according to claim 1, wherein said vapor separator is formed of a flexible material, and said vapor tube is formed integrally with said vapor separator. 4. An inner diameter of the vapor tube is 1 to 5 m.
The fuel tank for an automobile according to claim 1, wherein m is m.