TANK DEVICE FOR AN AQUEOUS UREA SOLUTION AND METHOD FOR REDUCING ICE PRESSURE IN A TANK DEVICE

Abstract

A tank device for an aqueous urea solution for injection into an exhaust system of a motor vehicle. The tank device includes a tank with a tank housing, an interior space located therein, a base and a cover. A separate base portion is attached to the tank housing and partially bounds the interior space. A lamella structure is formed on an upper side of the separate base portion, and the lamella structure has at least one lamella which at least partially subdivides the interior space of the tank above the base portion into a plurality of cells.

Claims

1. A tank device for injecting an aqueous urea solution into an exhaust tract of a motor vehicle, comprising: a tank; a tank housing having an interior, the tank housing being part of the tank; a base, the base being part of the tank; a top wall integrally formed with the base, the top wall being part of the tank; a separate base section, which is attached to the tank housing and partially extends into the interior of the tank housing; a lamellar structure which is formed on a top side of the separate base section; at least one lamella being part of the lamellar structure; and a multiplicity of cells, the at least one lamella dividing the interior of the tank above the base section at least partially into the multiplicity of cells; wherein the aqueous urea solution flows through the multiplicity of cells.

2. The tank device of claim 1, wherein the at least one lamella extends over an entire width of the top side of the base section.

3. The tank device of claim 1, the tank further comprising a maximum fill level, wherein the at least one lamella extends at least as far as the maximum fill level of the tank.

4. The tank device of claim 1, the at least one lamella further comprising at least one first passage.

5. The tank device of claim 1, wherein the lamellar structure is formed as a honeycomb body.

6. The tank device of claim 1, further comprising a tubular housing, wherein the lamellar structure is surrounded by the tubular housing.

7. The tank device of claim 6, the tubular housing further comprising at least one second passage.

8. The tank device of claim 1, wherein the at least one lamella tapers in an upward direction.

9. The tank device of claim 1, wherein the lamellar structure is made from a material being one selected from the group consisting of polyoxymethylene, HD polyethylene, and polypropylene.

10. A method for reducing a pressure in a tank device for an aqueous urea solution for injection into an exhaust tract of a motor vehicle, having at least the following steps: providing a tank device; providing a tank being part of the tank device; and providing a lamella structure having at least one lamella located inside the tank; filling the tank with an aqueous urea solution such that the at least one lamella is at least partially covered by the aqueous urea solution; freezing at least a portion of the liquid aqueous urea solution such that the frozen portion of aqueous urea solution surrounds a cavity of liquid aqueous urea solution, and the at least one lamella at least partially extends through the frozen portion of the aqueous urea solution, dividing the frozen aqueous urea solution into a plurality of cells; displacing the plurality of cells relative to one another as the portion of the aqueous urea solution freezes.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The invention and the technical field will be explained in more detail below on the basis of the figures. It should be pointed out that the figures show particularly preferred embodiment variants of the invention, to which the invention is however not restricted. Here, identical components in the figures are denoted by the same reference signs. The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:

[0041] FIGS. 1A-1D depict a freezing process of an aqueous urea solution in the case of a tank device without lamellar structure;

[0042] FIG. 2 is a sectional side view of a tank device having lamellar structure, according to embodiments of the present invention;

[0043] FIG. 3 is a perspective view of a base section having lamellar structure, according to embodiments of the present invention;

[0044] FIG. 4 is a partial cross-sectional view of lamellar structure, according to embodiments of the present invention; and

[0045] FIG. 5 is a side view of an alternate embodiment of a lamella, according to embodiments of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0046] The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.

[0047] FIG. 1 shows a freezing process of an aqueous urea solution 2 in a tank device 1 known from the prior art. The tank device 1 has, in images A, B, C and D, a tank 3 with an interior 4. Furthermore, the tank 3 has a base 19 with an opening 20 through which a separate base section 22 extends, which base section is in this case formed, by way of example, with a chamber housing with a pump 5 situated therein, and extends into the interior 4 of the tank 3. In image A, the aqueous urea solution 2 in the interior 4 of the tank 3 is liquid. In image B, owing to low outside temperatures, the aqueous urea solution 2 has frozen, to form frozen aqueous urea solution 18, in an outer region of the interior 4. As a result, a cavity 17 with aqueous urea solution 2 still in liquid form has formed in the frozen aqueous urea solution 18. In image C, the liquid aqueous urea solution 2 in the cavity 17 has frozen further, such that a pressure in the cavity 17 rises, the pressure acting on the base section 22. If the liquid aqueous urea solution 2 in the cavity 17 freezes further, as shown in image D, the pressure in the cavity 17 rises to a level that could cause the base section to be damaged (for example deformed or even pushed out of the tank housing 23).

[0048] FIG. 2 shows a sectional illustration through a tank device 1 with a lamellar structure. The tank device 1 has a tank 3 with an interior 4. The interior 4 is filled with aqueous urea solution 2 up to a maximum fill level 9. The tank 3 has, in a base 19, an opening 20 through which a separate base section 22 extends, which base section is in this case again formed, by way of example, with a chamber housing with a pump 5 situated therein, and extends into the interior 4 of the tank 3. A lamellar structure 6 is fastened to a top side 7 of the base section 22 by means of spot-welded connections. The lamellar structure 6 has a multiplicity of vertical lamellae 8 which divide the interior 4 of the tank 3 above the base section 22 into a multiplicity of cells 10. The multiplicity of lamellae 8 each have, at the top side 7 of the base section 22, first passages 13 through which the aqueous urea solution 2 may flow between the individual cells 10. Furthermore, the multiplicity of lamellae 8 are surrounded by a tubular housing 15, as is also seen in FIG. 2. The tubular housing 15 has a second passage 16 through which aqueous urea solution 2 may flow into the multiplicity of cells 10. If the aqueous urea solution 2 freezes to form frozen aqueous urea solution 18, the frozen aqueous urea solution 18 breaks at predetermined breaking points 11 formed by the multiplicity of lamellae 8. To assist this process, the multiplicity of lamellae 8 taper in the direction of a top wall 21 of the tank 3. In this way, damage to the base section 22 or to components situated therebelow, such as a pump 5, is prevented.

[0049] FIG. 3 shows a cylindrical, separate base section 22, which projects into the interior of the tank and has the lamellar structure 6, of the tank device 1 shown in FIG. 2. The lamellae 8 extend over an entire width 12 of the base section 22. Furthermore, the lamellar structure 6 is formed in the manner of a honeycomb body 14 which is surrounded by a tubular housing 15.

[0050] FIG. 4 now shows in detail, and in cross section, an edge region of a lamellar structure 6 with a tubular housing 15. It is seen that, in this cross section, first openings 13 are positioned in or on the individual lamellae 8, and also, second openings 16 are positioned in the tubular housing 15. Both sets of passages preferably directly adjoin the base section, though may be adapted with regard to form, number and/or size. The second openings 16 permit an exchange of flow (indicated by arrows) through the tubular housing 15, such that the cells 10 formed with or by the lamellar structure 6 may be filled with the aqueous urea solution from the tank and vice versa. An exchange of aqueous urea solution within adjacent cells 10 is permitted and ensured by means of the first openings 13.

[0051] Finally, FIG. 5 illustrates, in a front view (left) and in a side view (right) a preferred design variant of a lamella 8, which tapers upward, that is to say away from the base section 22, with a predefined angle 25. It is likewise seen that the lamella has multiple feet 24 between which the first openings 13 to the base section 22 are formed. The lamella 8 may also be non-detachably connected to the base section 22 by way of the feet 24.

[0052] The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.