EP2121370A1

EP2121370A1 - Fuel tank arrangement for a vehicle

Info

Publication number: EP2121370A1
Application number: EP08724183A
Authority: EP
Inventors: Johan Liljekvist
Original assignee: Scania CV AB
Current assignee: Scania CV AB
Priority date: 2007-02-27
Filing date: 2008-02-20
Publication date: 2009-11-25
Also published as: SE530889C2; WO2008105725A1; EP2121370A4; SE0700493L; BRPI0807931A2

Abstract

Fuel tank arrangement for a vehicle5 The present invention relates to a fuel tank arrangement (10) for a vehicle, in particular a heavyload vehicle, comprising a fuel tank (12) partitioned in a main tank compartment (16) and a catch tank compartment (18), wherein a fuel supply line (26) is arranged within said catch tank compartment (18) for supplying fuel out from said catch tank compartment (18) to a combustion engine of said vehicle, wherein said main tank compartment (16) and said catch tank compartment (18) are separated from each other by means of at least one partitioning wall (14). In order to provide a reliable and air-free fuel supply to a combustion engine, a valve mechanism (24) is arranged within said partitioning wall (24) which, depending on a filling condition within said main tank compartment (16), is opened or closed in response to sucking-in fuel via said fuel supply line (26).

Description

Fuel tank arrangement for a vehicle

The present invention relates to a fuel tank arrangement for a vehicle, in particular a heavy load vehicle, comprising a fuel tank partitioned in a main tank compartment and a catch tank compartment, wherein a fuel supply line is arranged within said catch tank compartment for supplying fuel out from said catch tank compartment to a combustion engine of said vehicle, wherein said main tank compartment and said catch tank compartment are separated from each other by means of at least one partitioning wall.

Such fuel tank arrangements are well known in the art. EP 0 803 394 Al, for example, describes such a fuel tank arrangement, wherein a catch compartment is arranged within a tank. Around the catch compartment a main tank compartment is included within the fuel tank. The catch compartment includes a check valve mechanism in order to prevent that in a low-filling state within the main tank compartment, fuel is flowing out from the catch tank compartment into the main tank compartment whereby the fuel supply to the combustion engine can be affected.

A similar solution known is FR 2,679,840, which also discloses a fuel tank arrangement having a main tank compartment surrounding a catch tank compartment within the fuel tank. The catch tank compartment is provided with inclined partitioning walls, wherein closing flaps are pivotable arranged within the catch tank compartment. These flaps allow an inflow of fuel through passages within the partitioning wall from the main tank compartment into the catch tank compartment but they prevent an unwanted outflow of fuel out of the catch tank compartment in a low-filling state of the main tank compartment.

A similar solution is also known from GB 2 413 784 A also showing a main tank compartment arranged within a fuel tank around a catch tank compartment. The catch tank compartment is arranged with pivotable flaps which allow an inflow of fuel from the main tank compartment but prevent an outflow of fuel out of the catch tank compartment into the main tank compartment.

It is an object of the present invention to provide a fuel tank arrangement according to the preamble of claim 1 which provides a reliable fuel supply to the fuel supply line. This object is solved by a fuel tank arrangement, in particular a heavy load vehicle, comprising a fuel tank partitioned in a main tank compartment and a catch tank compartment, wherein a fuel supply line is arranged within said catch tank compartment for supplying fuel out from said catch tank compartment to a combustion engine of said vehicle, wherein said main tank compartment and said catch tank compartment are separated from each other by means of at least one partitioning wall. According to the invention, a valve mechanism is arranged within said partitioning wall which, depending on a filling condition within said main tank compartment, is opened or closed in response to sucking-in fuel via said fuel supply line.

The valve mechanism therefore operates based on two conditions. The first condition is the filling condition within the main tank compartment. As long as the main tank compartment is in a high-filling condition, the valve mechanism provides a possibility of a fuel flow from the main tank compartment into the catch tank compartment.

Whenever a low-filling state within that main tank compartment is reached, the valve mechanism closes and therefore prevents an outflow of fuel from said catch tank compartment into said main tank compartment. Moreover, another operating condition of the valve mechanism is whether fuel is sucked in via said fuel supply line to the combustion engine. Without a sucking-in of fuel into said supply line, the valve mechanism does not actively open a passage between the main tank compartment and the catch tank compartment. Therefore, the requirement of fulfilling these two operating conditions for opening said valve mechanism guarantees that an unwanted outflow of fuel from said catch tank compartment into said main tank compartment in a low-filling state of said main tank compartment as well as sucking-in air from an empty main tank compartment into the fuel supply line can be efficiently prevented.

According to a further embodiment of the invention, said catch tank compartment is filled with fuel, primarily, wherein an overflow is provided for conducting excessive fuel into said main tank compartment, when said catch tank compartment is completely filled with fuel . This means, that when filling the fuel tank with fuel at a gas station, the fuel pours firstly into said catch tank compartment. As soon as said catch tank compartment is filled up, the excessive fuel pouring into the fuel tank then flows via the overflow from the catch tank compartment into said main tank compartment. Therefore, it can be guaranteed that the catch tank compartment is filled with fuel with a higher priority than said main tank compartment. With regard to the valve mechanism, one embodiment of the invention provides that said valve mechanism comprises a first valve member within said main tank compartment which opens a passage to said catch tank compartment, when the fuel within said main tank compartment exceeds a predetermined filling state, and which closes said passage to said catch tank compartment, when the fuel within said main tank compartment falls below said predetermined filling state. The first valve member therefore reacts in dependence on the filling condition of the main tank compartment. According to a particular embodiment of this aspect of the invention, that first valve member includes a float having a lower density than fuel. This means that the float tends to swim on the surface level due to its buoyancy.

According to the invention, it is possible that said float is a ball guided within a guiding duct between an open position and a closing position, wherein said guiding duct is arranged at the partitioning wall.

Alternatively, it is also possible that said first valve member includes an elastic valve lobe supporting said float and being movable between an open position and a closing position by means of said float.

With regard to the design of the valve mechanism on the catch tank compartment side, the invention can further provide that said valve mechanism includes a second valve member within said catch tank compartment, which opens and closes said passage in response to sucking-in fuel via said fuel supply line.

According to one embodiment with regard to this aspect of the invention, it can be provided that said second valve mechanism includes a ball guided within a guiding duct between an open position and a closing position, wherein said guiding duct is arranged at the partitioning wall and wherein said ball has a higher density than said fuel and wherein said ball is sucked into its open position when fuel is sucked into said supply line.

Alternatively, it can be provided that said second valve mechanism includes an elastic valve lobe being movable between an open position and a closing position, wherein said elastic valve lobe is sucked into its open position when fuel is sucked into said supply line.

A further aspect of the invention of the invention provides that said partitioning wall is inclined. In the following, the general operation as well as two embodiments of the invention are described with regard to the figures, wherein

Fig. 1 depicts a schematical perspective view of a fuel tank arrangement according to the invention;

Fig.2 schematically shows the fuel tank arrangement in a cross section;

Fig. 3 shows one embodiment of the valve mechanism;

Fig.4 shows an alternative embodiment of the valve mechanism according to the invention.

Fig. 1 shows a schematical perspective drawing of a fuel tank arrangement 10 for a vehicle. The fuel tank arrangement 10 includes a fuel tank 12, which is separated by a partitioning wall 14 into a main tank compartment 16 and a catch tank compartment 18. The partitioning wall 14 is arranged in an inclined manner. It is sealingly attached to the bottom and the sidewalls of the fuel tank 12, but it has an upper edge 20, which is freely arranged within the interior of the fuel tank 12 and forms an overflow for fuel, which will be explained in detail below. The partitioning wall 14 moreover comprises a substantially vertical foot portion 22. At this foot portion 22, a valve mechanism 24 is arranged, which allows a fluidic communication between the main tank compartment 16 and the catch tank compartment 18 under certain circumstances.

Fuel is drawn out of the catch tank compartment 18 by means of a fuel supply line 26, which has an open end within the catch tank compartment close to the valve mechanism 24 at the bottom of the fuel tank 12. Moreover, fig. 1 shows a fuel return line 28 for leading excessive fuel from the combustion engine back into the fuel tank 12. The fuel return line 28 has a free end opening at the bottom of the catch tank compartment 18.

Fig. 2 shows the fuel tank arrangement 10 in a schematical cross section with a certain filing state within the main tank compartment 16 and the catch tank compartment 18. Fig. 2 shows that in the main tank compartment 16, a fuel level 30 is prevailing, which is way below a fuel level 32 within the catch tank compartment 18. The fuel level 32 is determined by the upper edge 20 of the partitioning wall 14 which acts as an overflow. In this state, when additional fuel is filled into said catch tank compartment 18, it flows over the free edge 20 of the partitioning wall 14 into the main tank compartment 16. Fig. 2 also shows the fuel return line 28 leading a return fuel flow 34 into the catch tank compartment 18. Moreover, it shows the fuel supply line 26 leading a supply fuel flow 36 via a non-depicted fuel pump to a combustion engine of the vehicle. Moreover, fig. 2 shows a valve mechanism 24 as a "black box" wherein a fuel flow 38 represents the fuel flow from the main tank compartment 16 into the catch tank compartment 18.

The arrangement operates as follows:

As long as the filing condition within the main tank compartment 16 is sufficiently high, a fuel flow 34 is permitted by the valve 24 whenever fuel is sucked according to the fuel flow 36 through the supply line 26 to the fuel pump. However, as soon as the fuel level 30 further falls and reaches a minimum filling state within the main tank, which is close to the bottom of the fuel tank 12, the valve mechanism 24 shuts a passage within the foot portion 22 of the partitioning wall 14. Thus, it can be prevented that fuel flows out of the catch tank compartment 18 into the main tank compartment 16, which could affect an air-free fuel supply via the supply line 26.

Fig. 3 shows one embodiment of the valve mechanism 24. At the bottom end of the foot portion 22 of the partitioning wall 14, a passage 40 is arranged, which fluidically connects the main tank compartment 16 with the catch tank compartment 18. On the opposite orifices of the passage 40, sealing rings 42 and 44 are arranged. The fuel tank arrangement moreover includes in the crossing region of the foot portion 22 and the bottom of the fuel tank 12 wall portions 46, 48 and 50, which delineate guiding ducts 52 and 54. In said guiding duct 52, a valve ball 56 is arranged, which is movable between a lower position, wherein it closes the passage 40 on the side of the main tank 16, and an upper position 60 shown in dashed lines, wherein it releases this passage 40. The ball 56 has a lower density than the fuel stored within the fuel tank 12. Therefore, the ball 60 tends to swim on the surface level of the fuel, as far as permitted by the guide duct 52. When the fuel level within the main tank compartment 16 exceeds the upper position 60, the ball remains in this upper position 60 held by the wall portion 46.

The second guide duct 54 also receives a valve ball, namely the valve ball 48. This valve ball has a higher density than the fuel stored within the fuel tank 50. Therefore, the valve ball tends to maintain its position in a stationary state of the arrangement. However, when fuel is sucked by the fuel pump through the supply line 26 as represented by arrow 36, the ball 48 is sucked within the guide duct 54 in the direction of the open end of the supply line 26 and therefore opens the orifices of the passage 40 at the side of the catch tank compartment 18.

Due to this arrangement, the valve mechanism 24 of fig. 3 has the following operation. As long as there is sufficient fuel within the main tank compartment 16 and therefore the ball 56 maintains its upper position represented by reference numeral 60, a fuel flow from the main tank compartment 16 into the catch tank compartment 18 is possible, when fuel is sucked into the supply line 26. When a fuel supply to the combustion engines stops, the ball 48 prevents an outflow of fuel from the catch tank compartment 18 into the main tank compartment 16 by closing the passage 40 due to a sealing abutment to the sealing ring 44.

As soon as the fuel level within the main tank compartment 16 sinks to a level such that the ball 56 takes its position close to the passage 40, it closes the passage 40 by sealingly abutting against the sealing ring 42. Thus, even if fuel is sucked through the supply line 26 out from the catch tank compartment 18, the ball 56 keeps the passage 40 closed and therefore prevents sucking-in air into the catch tank compartment and into the supply line 26.

Fig. 4 shows an alternative embodiment of the valve mechanism. Instead of balls as shown with regard to the embodiment according to fig. 3, on opposite sides of the passage 40, two lobes 62 and 64, formed from elastic rubber material are fixed to the foot portion 22 of the partitioning wall 14. The lobes 62, 64 are fixed to the foot portion 22 by means of rivets 66 or similar fixing means. The lobe portion 62 is provided at its movable free end with a float 68, which has a substantially lower density than the fuel stored within the fuel tank 12. The two elastic rubber lobes 62 and 64, however, do have a higher density compared to the fuel stored in the fuel tank 12.

The functioning of the valve mechanism 24 according to fig. 4 is similar to that described with regard to fig. 3. The float 68 provides that the lobe 62 is held in a position where it releases the passage 40 as long as there is sufficient fuel within the main tank compartment. This is due to the fact that the float 68 tends to swim on the upper surface level of the fuel contained in the main tank compartment 16. Due to the elasticity of the lobe 64, it is pressed against the foot region 22 enclosing the passage 40 as long as the hydraulic pressure within the catch tank compartment 18 is higher than in the main tank compartment 16. When fuel is sucked into the supply line 26 as represented by arrow 36, and as long as at the same time there is sufficient fuel within the main tank compartment 16 such that the float 68 keeps the lobe 62 away from the passage 40, a fuel flow from the main tank compartment 16 through the passage 40 is possible as the lobe 64 is flapped away, as shown in fig. 4. However, as soon as the fuel level within the main tank compartment 16 falls down to a level close to the passage 40, the float 68 takes the position of the fuel level and therefore the lobe 62 can close the passage 40 on the side of the main tank compartment 16. Moreover, the lobe 64 is pressed against the region around the passage 40 and therefore closes the passage 40. Thus, fuel is merely sucked out from the catch tank compartment 18.

The invention provides an easily structured but reliable arrangement to guarantee an air-free fuel supply to a combustion engine.

Claims

1. Fuel tank arrangement (10) for a vehicle, in particular a heavy load vehicle, comprising a fuel tank (12) partitioned in a main tank compartment (16) and a catch tank compartment (18), wherein a fuel supply line (26) is arranged within said catch tank compartment (18) for supplying fuel out from said catch tank compartment (18) to a combustion engine of said vehicle, wherein said main tank compartment (16) and said catch tank compartment (18) are separated from each other by means of at least one partitioning wall (14), characterized in that a valve mechanism (24) is arranged within said partitioning wall (24) which, depending on a filling condition within said main tank compartment (16), is opened or closed in response to sucking-in fuel via said fuel supply line (26).

2. Fuel tank arrangement (10) according to claim 1, characterized in that said catch tank compartment (18) is filled with fuel, primarily, wherein an overflow (20) is provided for conducting excessive fuel into said main tank compartment (16), when said catch tank compartment (18) is completely filled with fuel.

3. Fuel tank arrangement (10) according to claim 1 or 2, characterized in that said valve mechanism (24) comprises a first valve member within said main tank compartment (16) which opens a passage (40) to said catch tank compartment (18), when the fuel within said main tank compartment (16) exceeds a predetermined filling state, and which closes said passage (40) to said catch tank compartment (18), when the fuel within said main tank compartment (16) falls below said predetermined filling state.

4. Fuel tank arrangement (10) according to claim 3, characterized in that said first valve member includes a float (56;68) having a lower density than fuel.

5. Fuel tank arrangement (10) according to claim 4, characterized in that said float is a ball (56) guided within a guiding duct (52) between an open position and a closing position, wherein said guiding duct (52) is arranged at the partitioning wall (14).

6. Fuel tank arrangement (10) according to claim 4, characterized in that said first valve member includes an elastic valve lobe (62) supporting said float (68) and being movable between an open position and a closing position by means of said float (68).

7. Fuel tank arrangement (10) according to one of claims 3 to 6, characterized in that said valve mechanism (24) includes a second valve member within said catch tank compartment (18), which opens and closes said passage (40) in response to sucking-in fuel via said fuel supply line (26).

8. Fuel tank arrangement (10) according to claim 7, characterized in that said second valve mechanism includes a ball (48) guided within a guiding duct (54) between an open position and a closing position, wherein said guiding duct (54) is arranged at the partitioning wall (14), wherein said ball (48) has a higher density than said fuel and wherein said ball (48) is sucked into its open position when fuel is sucked into said supply line (26).

9. Fuel tank arrangement (10) according to claim 7, characterized in that said second valve mechanism includes an elastic valve lobe (64) being movable between an open position and a closing position, wherein said elastic valve lobe (64) is sucked into its open position when fuel is sucked into said supply line (26).

10. Fuel tank arrangement (10) according to one of said preceding claims, characterized in that said partitioning wall (14) is inclined.