JP2645958B2 - 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 when the engine is overheated, particularly when the fuel is restarted after the engine is stopped.

[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 shapes and dimensional relationships of the fuel pump and the vapor separator, that is, the vapor separator are not clear, but they need to be formed in a small size. It is required that the cross-sectional area of the main body be as small as possible. For example, if the shape of the vapor separator described in the above-mentioned publication is assumed to be cylindrical, the diameter of the cross section of the fuel discharge portion is formed as small as possible.

[0005] In this case, if the cross section of the fuel discharge portion is too small, a gas layer and a liquid layer are alternately formed in the fuel discharge portion when the vapor contained in the fuel is separated by the vapor separator. There is. For this reason, air bubbles are formed in the fuel, and the air bubbles are repelled at the fuel level in the tank main body, resulting in abnormal noise. To prevent this, the vapor separator may be formed in a large size, but this would be against the demand for miniaturization.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a fuel tank for a vehicle having a vapor separator provided at a discharge port of a return tube so that the generation of the abnormal noise can be suppressed without increasing the size of the vapor separator. .

[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, wherein the vapor separator is provided with a vapor separator 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.
Housing or the formation of the vapor discharge port at one end so as to form
The return tube is inserted through one opening of the housing to form a gas-liquid separation portion that accommodates the discharge port of the return tube in the housing, and the other opening of the housing is A fuel discharge portion having a flat cross section including the fuel discharge portion is formed, and the hollow portion of the fuel discharge portion is disposed so as to extend vertically in the tank body.

In the fuel tank for an automobile, it is preferable that the vapor separator is formed such that a longitudinal dimension of a cross section of the fuel discharge portion is twice or more a width dimension.

Further, the opening of the casing on the side of the fuel discharge portion is
The fuel discharge portion may be formed so as to be located on the longitudinal axis of the cross section of the fuel discharge portion.

[0010]

In the fuel tank for an automobile having the above structure, the vapor separator provided at the discharge port of the return tube comprises a casing having openings at both ends and a vapor discharge port formed at one end. A return tube is inserted through one of the openings, and a discharge port of the return tube is accommodated in the housing to form a gas-liquid separation portion. Also,
A flat cross section fuel discharge portion including the other opening of the housing is formed, and the hollow portion of the fuel discharge portion is arranged so as to extend vertically in 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 and discharged from the opening through the fuel discharge portion having a flat cross-sectional shape, even if the fuel contains vapor, the fuel flows into the gas-liquid separation portion of the vapor separator. Thus, gas-liquid separation is appropriately performed, and no bubbles are formed at the fuel discharge portion. Therefore, the abnormal noise that can be generated in the gas-liquid separation section is reliably blocked by the vapor separator, and no new noise is generated in the fuel discharge section.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 shows the overall configuration of a fuel supply system including an automobile fuel tank according to one embodiment of the present invention. Liquid fuel (hereinafter, referred to as engine E)
Simply referred to as fuel). 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. Body 2
It is connected to the. A fuel filter 5 is interposed in the main tube 4, and a pulsation damper P for attenuating the pulsation of the supply fuel pressure is provided at the inlet of the delivery tube D.

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 the mounting plate 9, The fuel pump 3 is supported at the other end via a cushion rubber or the like.

A main tube 4 and a 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 this embodiment is formed by forming a circular hole 8c and a notch 8d continuous with the hole 8c and having a width smaller than the diameter of the 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 oval (L> W) flat cross-sectional shape shown in FIG. 7, and has an opening 12 for discharging fuel at an end. That is, as shown in FIG. 7, the cross-sectional shape of the fuel discharge portion 10b is formed such that the length L in the longitudinal direction is twice or more (L ≧ 2W) the width W in the width direction. And the opening 12 on the discharge side is
It is formed so as to be located on the longitudinal axis of the cross section of the fuel discharge portion 10b.

As shown in FIGS. 5 and 8, an engaging portion 8 is provided on the side wall of the fuel discharge portion 10b of the vapor separator 10.
An engagement projection 14 having a head portion 14a having a larger diameter and a neck portion 14b having a smaller diameter is formed so as to bulge out of the hole 8c of b. When the vapor separator 10 is supported on the bracket 8, the return tube 6 is first inserted into the opening 11, and the neck 1 of the engaging projection 14 is moved while the vapor separator 10 is slid.
4b is fitted into the notch 8d of the engaging portion 8b, and pressed until the neck 14b is positioned in the hole 8c. Thereby, both ends of the vapor separator 10 are connected to the return tube 6 and the engaging portion 8b.
Will be supported by 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 mounted as described above is arranged in the sub tank 7 of the tank body 2 as shown in FIG. 1, and the fuel is supplied to the tank body 2 as much as possible (commonly called full tank). At this time, as shown in FIG. 10, the tip of the vapor tube 20 is disposed so as to protrude above the maximum fuel liquid level FLm by a height H. At this time, the fuel discharge opening 12 opens in a direction in which a flow in the same direction as the flow direction of the fuel flowing into the sub-tank 7 from the tank body 2 via the communication path is formed.

In the fuel tank for an automobile having the above 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 6a of the return tube 6 into the vapor generator 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 the vapor generated when the fuel passes through the engine E. This vapor is separated when the fuel is discharged from the discharge port 6a, and the fuel is separated from the vapor discharge port. 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 inside the tank body 2 is communicated with a canister (not shown) through 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 show comparative examples.
While the cross-sectional shape of the fuel discharge portion 10b of the vapor separator 10 in one embodiment of the present invention is flat as described above and the opening 12 is formed on the longitudinal axis, the fuel discharge portion of the comparative example The portion 10b is thin and has a substantially square cross section. In the vapor separator 10 of this comparative example, when the fuel is discharged from the return tube 6 as shown in FIG. 11, a liquid layer is formed so as to close the hollow portion of the fuel discharge portion 10b as shown in FIG.
A gas layer is formed between the vapor separator 10 and the fuel liquid level. After the liquid layer has flowed down, a new liquid layer is formed by the fuel from the return tube 6, and FIG.
As shown in (1), a gas layer is formed between the above-mentioned liquid layer.
When the liquid layer and the gas layer are formed alternately in this manner, bubbles are continuously formed as shown in FIG. 14, and sequentially flow out of the opening 12 into the fuel in the sub-tank 7. Thus, when these air bubbles are released into the tank main body 2, the air bubbles are popped and generate an abnormal noise.

On the other hand, in this embodiment, the fuel discharge portion 10b is formed in a flat cross section as shown in FIGS. 5 to 8, and the hollow portion of the fuel discharge portion 10b is formed in the vertical direction as shown in FIG. The fuel discharged from the return tube 6 flows down along the inner wall surface below and on the right side of the vapor separator 10. For this reason, the liquid layer is formed in close contact with the inner wall surface, and a gas layer is formed between the upper and left inner wall surfaces of the vapor separator 10, so that both layers do not polymerize. As described above, according to the present embodiment, no air bubbles are formed in the fuel discharged from the opening 12 of the fuel discharge portion 10b, and therefore, no abnormal noise is generated.

According to the experimental results, it is desirable that the cross-sectional shape of the fuel discharge portion 10b is such that the length L in the longitudinal direction is at least twice the width W in the width direction. When the flow rate of the fuel to be used is 70 to 100 liters / hour, L is set to 30 mm and W is set to 1
The optimum value is 0 mm.

FIGS. 15 and 16 show a vapor separator 100 according to another embodiment of the present invention. The bracket 80 has a long hole 80b and a long hole 80c.
The distal end portion 60 of the return tube 60 bent in an L shape
a is arranged so as to protrude above the bracket 80 through one of the long holes 80b. In addition, the opening 110 and the engaging projection 140 are formed on the same side surface (the lower side surface in FIG. 15) of the vapor separator 100 as shown in FIG.
Is formed. The opening 120 on the side of the fuel discharge portion 100b is formed so as to be located on the longitudinal axis of the cross section of the fuel discharge portion 100b. It is formed so as to be discharged along the inner wall surface (not shown). That is, in the present embodiment, the flow of the fuel flowing from the tank main body 2 into the sub-tank via the communication path is configured to be in the opposite direction to that of the above-described embodiment, and the opening 120 as shown in FIG. Since the fuel is discharged in the same direction as the flow of the fuel, it is opened in a direction opposite to the opening 12 of the above-described embodiment.

A cylindrical portion 111 having a predetermined thickness is formed around the opening 110 of the vapor separator 100, and a rib 1 connecting the cylindrical portion 111 to the main body of the vapor separator 100.
12 and 113 are integrally formed, and rigidity for supporting the vapor separator 100 on the return tube 60 is ensured. Further, the vapor discharge port 130 is shown in FIG.
As shown in FIG. 6, an opening is formed in the direction along the side surface of the vapor separator 100, and a vapor tube 200 made of a flexible material bent in a substantially rectangular shape is attached to the opening as shown in FIG.

In the fuel tank having the vapor separator 100 constructed as shown in FIGS. 15 and 16, the vapor separator 100 is mounted on the bracket 80 from above in FIG. If the discharge port 60a at the end of the return tube 60 is
And the engaging projection 140 is inserted into the elongated hole 80c of the bracket 80 and locked.

As described above, the vapor separator can be formed in various shapes, and may be arranged laterally with respect to the bracket, or may be arranged above or below. In any arrangement, the opening on the fuel discharge section side is located on the longitudinal axis of the cross section of the fuel discharge section and is formed so as to be in the same direction as the flow of the fuel flowing into the sub tank. Therefore, the flow of the fuel from the fuel discharge portion facilitates the flow of the fuel from the tank body into the sub-tank.

[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 fuel recirculated to the tank body via the return tube is discharged from the return tube into the vapor separator and discharged from the opening via the flat cross-section fuel discharge portion. It is configured as
Even if vapor is contained in the recirculated fuel, gas-liquid separation is appropriately performed in the gas-liquid separation section of the vapor separator, and bubbles are formed in the fuel discharge section and released into the fuel in the tank body. This does not occur. Therefore, the abnormal noise that can be generated at the time of gas-liquid separation can be reliably blocked by the vapor separator, and the generation of new abnormal noise in the fuel discharge section can be prevented.

In particular, in the case of a fuel cell having a vapor separator formed such that the length in the longitudinal direction of the cross section of the fuel discharge portion is at least twice the size in the width direction, the formation of bubbles in the fuel discharge portion is reliably prevented. be able to.

Further, in the case where the opening of the casing of the vapor separator on the side of the fuel discharge portion is formed so as to be positioned on the longitudinal axis of the cross section of the fuel discharge portion, the fuel from the fuel discharge portion is formed. The flow facilitates the flow of fuel from the tank body into the sub-tank.

[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 sectional view of a vapor separator in a comparative example.

FIG. 12 is a sectional view of a vapor separator in a comparative example.

FIG. 13 is a sectional view of a vapor separator in a comparative example.

FIG. 14 is a sectional view of a vapor separator in a comparative example.

FIG. 15 is an assembled perspective view of a fuel pump and a vapor separator mounted on a bracket according to another embodiment of the present invention.

FIG. 16 is a perspective view of a vapor separator according to another embodiment of the present invention.

[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 (3)

(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.
Housing or the formation of the vapor discharge port at one end so as to form
The return tube is inserted through one opening of the housing to form a gas-liquid separation portion that accommodates the discharge port of the return tube in the housing, and the other opening of the housing is A fuel tank for a vehicle, wherein a fuel discharge section having a flat cross-sectional shape is formed, and a hollow portion of the fuel discharge section is arranged so as to extend vertically in the tank body. 2. A fuel tank for an automobile according to claim 1, wherein said vapor separator is formed such that a dimension in a longitudinal direction of a cross section of said fuel discharge portion is twice or more as large as a dimension in a width direction. . 3. The fuel tank for an automobile according to claim 2, wherein an opening of the casing on the side of the fuel discharge section is formed so as to be located on an axis in a longitudinal direction of a cross section of the fuel discharge section. .