FUEL TANK

Abstract

Fuel tank for a motor vehicle having a tank housing (1) that encapsulates a fuel space (2) divided by means of a number of lateral stiffening partitioning wall (4, 5) into fuel chambers (8, 9). These communicate with each other via openings (10-15) in the partitioning walls. The tank exhibits an outlet member (116) with a chosen position in one of the fuel chambers where the opening is delimited all around by means of an opening edge (26) which is arranged within the partitioning wall with a distance to the bottom of the tank. In one or more of the openings between the fuel chambers, a back valve (22) is arranged. By means of the clack valve, flow is permitted to the fuel chamber (7) with the outlet member (16), but in the opposite direction the flow is completely or partially prevented by means of which, in case of a sloping of the tank in its longitudinal direction, fuel is retained in the fuel chamber in which the outlet member is positioned.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation patent application of International Application No. PCT/SE03/01205 filed 14 Jul. 2003 which was published in English pursuant to Article 21(2) of the Patent Cooperation Treaty, and which claims priority to Swedish Application No. 0202268-9 filed 19 Jul. 2002. Said applications are expressly incorporated herein by reference in their entireties.

FIELD OF THE INVENTION

The present invention relates to a fuel tanks; and more particularly to fuel tanks for vehicles.

BACKGROUND OF THE INVENTION

Fuel tanks, such as those used in vehicles, are usually partitioned into sections with intermediate walls in order to prevent the fuel from sloshing around in the tank when driving (accelerating and turning) about and braking due to the risk that the fuel's relative position (level) within the tank can change so much that it falls below the opening of the outlet pipe. When a vehicle is oriented at a slope and the fuel level is low, it is still possible to end up with the fuel level being below the opening of the fuel outlet pipe, with the consequence being that the engine stalls because of lack of fuel and stops running.

SUMMARY OF THE INVENTION

A primary purpose or objective of the present invention is to provide a fuel tank in which the above-described disadvantage(s) are reduced. This purpose is obtained at least in part by way of the invention's arrangement in which fuel is retained where the fuel outlet (member) is positioned so that the influence of a shifting fuel level is reduced, especially when the vehicle is oriented at an angle (with respect to horizontal) and therefore the risk of operational interruption is reduced.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described in greater detail hereinbelow with reference to two embodiments depicted in the accompanying drawings, and in which:

FIG. 1 is a schematic view showing a longitudinal cross section taken through a fuel tank configured according to a first embodiment of the invention;

FIG. 2 is an enlarged, detail view of a portion of an intermediate wall of the fuel tank of FIG. 1;

FIG. 3 is a cross sectional view of the fuel tank along the line 111-111 in FIG. 1;

FIG. 4 is a schematic view showing a longitudinal, horizontal cross section through a fuel tank configured according to a second embodiment of the invention;

FIG. 5 shows the fuel tank of FIG. 4, but in a sloping position; and

FIG. 6 shows a cross section through the fuel tank of FIG. 1 taken along the line VI-VI in FIG. 5.

DETAILED DESCRIPTION

For the sake of simplicity, the accompanying figures only show a fuel tank as such. The tank is intended to be arranged in a motor vehicle, primarily a truck, in order to provide fuel to the engine during operation. The tank is normally elongate, and suspended by suspension means (that are not shown) at the outside of the main beam of the vehicle frame, on the right or left hand side. The tank is normally horizontally positioned when the vehicle is in a horizontal position.

With reference first to FIGS. 1, 2 and 3 which show a first embodiment of the invention, it will become evident that the fuel tank comprises (includes, but is not necessarily limited to) a tank housing 1 which encapsulates a space 2 for fuel 3 in liquid form. The fuel tank is configured into sections that are exemplarily partitioned into a number of sections by means of one or more intermediate (partitioning) walls 4, 5. As exemplarily shown, the walls 4, 5 extend across the fuel tank at a straight angle to the longitudinal direction of the fuel tank and as indicated by the arrow 6 which usually corresponds to the driving direction of the vehicle. The partitioning walls 4, 5 divide (partition) the fuel tank into sections (a plurality of sections) or fuel chambers 7, 8, 9 which in the example are shown to number three. The tank housing 1 is outwardly delimited by casing walls, in the first example an upper wall 35, a lower wall 36 (the bottom) and side walls 37, 38 and two gable walls 39,40. In each partitioning wall 4, 5, there is arranged one whole or through-going opening; in the illustrated example, there are three openings 10-15, of which the uppermost two are always open so that the chambers on each side of the partitioning wall are in connection with each other and permit the flow of fuel in both directions. The partitioning walls 4, 5 also have a stiffening influence on the casing walls 36, 36, 37 of the tank housing 1, whether the tank is box shaped as in the embodiment in FIG. 3, or cylindrical as in the embodiment of FIG. 6 or a combination of these. Advantageously, the partitioning walls are in direct contact with the casing walls all around. Also, there are fastening devices such as consoles with tightening bands 41, 42 (see FIG. 1) arranged in front of the partitioning walls 4, 5 i.e. where the tank is at its stiffest.

In one of the chambers (in the example of FIG. 1 it is the forward chamber 7 as seen in the driving direction), an outer member 16 is arranged on top of the top side 17 of the tank where the external fuel pipe (to the engine that is driven with the fuel) is attached to the outlet member, usually referred to as a tank armature, and which also comprises a sensor for the fuel level. In the outlet member 16, a suction pipe 18 is included that protrudes downwards in the center 7 and ends downwards with an outlet opening 19 for the fuel. The opening is positioned slightly above the bottom in order to avoid bottom sediment, condensed water and other undesirable substances to be sucked up into the suction pipe which communicates with the external fuel pipe. The suction is obtained by means of a not shown fuel pump. Furthermore, the tank is provided with filling members 21 in the form of a closable filling opening provided with a tank lid. The filling member is, in the example shown, positioned on the top of the tank and can also be oriented towards the upper, outer, elongate corner portion of the tank. In the example shown, the filling member 21 for fuel is positioned above the middle chamber, which means that the filling is carried out first in this chamber, following which fuel flows via the openings 10, 15 over to the two other chamber 7, 9.

According to the invention, a bottom opening 12 in at least one of the partitioning walls 4 is provided with a clack valve 22, which is thus arranged to permit flow in only one of the directions from the one chamber 8 to the other chamber 7, but to block or at least severely restrict flow through this opening to this opposite direction. The back valve is turned so that it permits flow in the direction in towards the chamber 7, where the outer member 16 is positioned, i.e in the example shown from the intermediate chamber 8 to one of the outer chambers 7, in the example shown the front chamber.

FIG. 2 in more detail shows a simple example of the embodiment of the clack valve in the shape of a pivotally arranged valve 24 arranged above the opening 12 in a point 23, which valve is of such shape and size that it can close the opening entirely when it swings down towards that side 25 of the partitioning wall 24, which faces the chamber 7. The valve can be a completely sealing covering disk which is dimensioned and positioned to cover the opening 12, and is thus arranged to be able to be in contact with the circumference edge 26 around the opening 12; i.e., overlapping the edge 26 and by means of the pressure difference on the two sides and the valve so that the tendency towards rearwards flow is prevented, i.e. in the backwards direction from the chamber 7 to the chamber 8. In the case of flow in the opposite direction, from the chamber 8 to the chamber 7, the valve 24 opens due to overpressure in the chamber 8 and thus towards the opening 12. In a static position or resting position, the clack valve 22, is closed, i.e. the valve 24 hangs down and seals against the circumference edge 26. The circumference edge 26 is in its entirety shaped by the partitioning wall 4, i.e. the circumference edge 26 at the bottom 20 of the tank is at a distance from this, so that the valve 24 exclusively seals against the partitioning wall 4 and not against the bottom, by means of which sealing is also ensured in case of a deformation of the bottom.

In the example shown in FIGS. 1-3, the bottom edge of the lower opening 12 is positioned essentially at the same level as the outlet opening 19 of the outlet member, or just above this level. When the fuel tank is in the horizontal position or in an essentially horizontal position, there are no problems with fuel feeding out of the tank so long as the fuel (shown by means of a horizontally dotted line 27) is above the outlet opening 19. In the case of a fuel tank which does not have a clack valve, as exemplarily shown, the fuel level 28 easily drops below the outlet opening 19, with operational interruptions as a consequence as demonstrated by the sloping dotted line 28.

When a fuel tank configured according to the teachings of the present invention experiences the same type of low fuel level as described immediately above (the tank becomes inclined/declined as a result of the carrying vehicle being on a slope relative to the direction of travel 6), the clack valve 22 is kept closed due to the influence of the fuel pressure in the fuel chamber 7. This prevents the fuel in a fuel chamber 7, even at the beginning of a slope, from flowing to the other two fuel chambers 8, 9 so that it is maintained the front fuel chamber around the suction pipe 18 with an unchanged level as indicated by the upper leaning dotted line 30. This unchanged line occurs on the condition that the suction pipe 18 is positioned essentially symmetrically in the fuel chamber 7 as regards at least the longitudinal direction of the chamber as shown in FIG. 1. Regardless of the position of the suction pipe in the fuel chamber, the fuel level will, due to the clack valve, be kept at a higher level than would have been the case if there had been no clack valve—and this reduces the risk of the outlet opening 19 being above the fuel level.

When the vehicle travels along an essentially horizontal road and the fuel tank is in an essentially horizontal position, or when the vehicle is positioned in a downwards slope as seen in the direction of travel, fuel can freely flow between the fuel chambers by means of the clack valve 22 being kept open. As a result, fuel can continuously flow over to the front fuel chamber where the outlet member is positioned; a feature that is a necessary condition for utilization of the fuel from the other chambers.

In a second embodiment as illustrated in FIGS. 4, 5 and 6, parts that correspond to like parts of the first embodiment have been given corresponding reference numerals, with the addition of 100. Thus, the fuel tank according to the second embodiment comprises a tank housing 101 which encapsulates a space 102 for the fuel 103. This fuel tank is also sectioned; that is, partitioned into a number of sections by means of partitioning walls. In the example shown, two partitioning walls 104 and 105 extend across the fuel tank; i.e., perpendicularly with respect to the longitudinal direction of the fuel tank as indicated by the arrow 106 which corresponds to the direction of travel of the vehicle. In this example, it will become clear that the partitioning walls can be bent in order to better resist pressure differences between the three sections or fuel chambers 107,108, 109, which are usually also referred to as sloshing walls. The fuel chambers 7, 8 and 9 are to a certain degree in communication with each other via large holes 110-112 in the partitioning walls and which are at different levels in each wall. For example, three such holes are shown in the (each) wall in the cross section of FIG. 6. These holes are in this example continuously open, and are relatively large in order to freely permit flow of fuel between the chambers on the condition that the fuel level reaches up to each opening.

The outlet member 116 is attached to the tank on its topside 117, and is connected to the fuel pipe at that location, and which, via a fuel pump (that is not shown) leads to the vehicle engine that is fuelled by means of the fuel in the tank. From the fuel tank, there is a stiff suction pipe 18 that protrudes downwards into the tank to a level where the pipe ends with an opening 19 at a distance above the bottom 120 of the tank. In practice, the opening can consist of several smaller openings which can be directed sideways at the lower end of the pipe and include a fuel filter in order to prevent particles being swept along from the bottom of the tank. To this end, the opening 119 is thus not arranged immediately at the bottom. The filling member 121 is placed at a higher level of the tank, and in the example shown, in the same fuel chamber as the outer member 116. In this case, both the outlet member and the filling member 121 are placed in the middle fuel chamber, but can in principle be placed in any of the other chambers and also in different chambers. The advantage of symmetrically, centrally placed outer members 116, is that the same tank can be placed either to the right or the left of the vehicle with the same length of the fuel conduit. It can in this context be an advantage that the filling member is also centrally placed.

According to the invention, the fuel tank of the second embodiment is also provided with an arrangement to permit the flow of fuel at a low level through the respective partitioning walls 104, 105 in one of the directions from a chamber to an adjacent chamber. The arrangement also blocks, or severely limits flow in the opposite direction. In the second embodiment, clack valves 131, 132 are arranged in the two partitioning walls 104, 105. These are also arranged in separate openings 133, 134 at a lower position in a respective partitioning wall; i.e., below the other openings 110, 111, 112. The clack valves can in their simplest embodiment be designed in the same way as in the first embodiment; that is, in the form of a pivotally suspended valve 124 at a point 123 above the opening which is arranged to, in closed position, to seal the entire opening 133, 134, but to also swing outwards in the case of overpressure of the opposite side of the partitioning wall.

When driving on an essentially horizontal road (shown in FIG. 4 with an essentially horizontal fuel level 127), fuel is permitted to flow from the two outer fuel chambers 107, 109 to the intermediate chamber 108 where the outlet member 116 is positioned. When the vehicle leans in its longitudinal direction in either direction of slope, for example with a slope according to FIG. 5 as indicated by the arrow 106, the fuel attempts to flow to the lowermost part of the fuel tank. Due to the pressure difference on the two sides of the clack valve in the lowermost positioned partitioning wall 104, the clack valve 101 is kept closed, while the clack valve 132 is kept open. This results in the fuel being prevented from flowing from the middle fuel chamber to the lower fuel chamber 127 as soon as the slope begins, while fuel is still permitted to flow from the uppermost fuel chamber 109 to the middle fuel chamber. This ensures that the fuel level 128 at the outlet opening 119 is at a level at least not lower than the level of the horizontal position, but is even at a slightly higher level.

Important aspects concerning the fuel level are that the through flow of the clack valve of the respective openings 133, 134 in the partitioning walls 104,105 be below the fuel consumption of the engine; that is, the flow in the outlet member 116. Another important aspect is the height, H, from the bottom of the tank 120 to the lower most part of the larger through flowing holes 112 as is the distance, D, between the partitioning walls 104, 105.

Another advantage with the second embodiment is that a very limited filling of an empty tank will give a better degree of utilization of the volume available since the clack valves 131, 132, when filling in the horizontal position, are kept closed and through flow does not take place until the fuel level reaches the most large overflow opening 112.

It should be appreciated that invention is not limited to that which is described above and shown in the drawings, but can be varied in different ways and still be within the scope of the patented claims.

For example, a number of intermediate walls can be present, or just one single partition can be implemented that divides the fuel area into two fuel chambers. For example, there can be one, two, three or even more partitioning walls. The filling member can in principle be positioned in any of the fuel chambers, for instance, w either of the outer chambers. In a tank with three partitioning walls, four chambers are obtained—two outer chambers and two intermediate chambers, but the filling member can still be positioned in any of the chambers.

It should also be appreciated that larger overflow holes can also be positioned and arranged in a manner different than that which has been shown. Above, the example shows essentially rectangular cross section(s) and circular cross section(s)—but it is also possible to combine the two shapes so that there is an asymmetrical cross section of shape, for example an essentially rectangular cross sectional shape of one side of a vertical axis of symmetry, and a semicircular cross sectional shape on the other side. Among other configurations, partitioning walls can be oblique, and directed and shaped in other ways.

The expression casing wall(s) of the tank refers to that or those walls which encapsulate the tank with the exception of the gable walls regardless of shape. Furthermore, the tank housing is manufactured in a material of even thickness such as steel plating, preferably stainless steel, but plastic tanks with a homogenous wall thickness are also possible.

Claims

1. A fuel tank for motor vehicles comprising:

a tank housing encapsulating a fuel space divided by at least one lateral stiffening partition wall into a plurality of fuel chambers, said fuel chambers being in fluid communication via a plurality of partition wall openings;

an outlet member positioned in one of the fuel chambers; and

a clack valve arranged at one of said openings between the fuel chambers thereby establishing a valved opening, said valved opening being circumferentially delimited by an opening edge configured in the partition wall and positioned at a distance from a bottom of the tank, said clack valve being arranged to permit flow to the fuel chamber having the outlet member and to at least partially prevent flow in an opposite direction so that when the tank is inclined relative to a longitudinal direction thereof, fuel is retained in the fuel chamber with the outlet member.

2. The fuel tank as recited in claim 1, further comprising:

a bi-directional flow opening arranged at a height above the bottom of the tank above said valved opening.

3. The fuel tank as recited in claim 2, further comprising:

at least two partition walls, one of which has a lower opening provided with a clack valve and with the outlet member being positioned in an outer chamber delimited by a partition wall with a clack valve.

4. The fuel tank as recited in claim 1, further comprising:

at least two partition walls, both of which have a lower opening provided with a clack valve arranged to permit flow from an outer chamber to a middle chamber in which the outlet member is positioned.

5. The fuel tank as recited in claim 4, further comprising:

a filling member of the tank being connected to the tank housing at one of the outer chambers.

6. The fuel tank as recited in claim 2, further comprising:

three partitioning walls wherein lower openings in the partition walls are provided with clack valves which are arranged to allow flow from the outer chambers to the chamber where the outlet member is positioned.

7. The fuel tank as recited in claim 2, further comprising:

four partitioning walls in which a lower opening in each is provided with a clack valve arranged to allow flow to the chamber where the outer member is positioned.

8. The fuel tank as recited in claim 3, further comprising:

said filling member of the tank being connected to the tank housing in middle chamber.

9. The fuel tank as recited in claim 1, wherein each partitioning wall is arranged with two openings that permit bi-directional flow.

10. The fuel tank as recited in claim 1, wherein a lower opening is provided with a clack valve and three other openings permit flow in both directions and are positioned at different heights.

11. The fuel tank as recited in claim 1, wherein the tank is attached to a frame of the vehicle by fastening devices so that the tank comprises at least two partitioning walls, each having fastening devices that extend around the tank at positions that include at least two of the partitioning walls.