Urea tank and base plate with an integrated heating element

Abstract

Urea tank and base plate with an integrated heating element in which the heating element comprising at least one resistive track affixed to one flexible film and/or placed between two flexible films.

Claims

1. A urea tank comprising: an integrated heating element comprising at least one flexible heating part which is a flexible heater comprising at least one resistive track placed between two flexible films made of plastic, and a substantially cylindrical support including a plurality of openings, wherein the flexible heater comprises a body and a plurality of excrescences that extend from the body and are equipped with at least one part of the resistive track, each of the excrescences passing through a respective one of the openings.

2. The urea tank according to claim 1, wherein the plastic is polyolefin.

3. The urea tank according to claim 2, wherein the polyolefin is polyethylene.

4. The urea tank according to claim 2, wherein the polyolefin is polypropylene.

5. The urea tank according to claim 1, wherein a flexural rigidity of the flexible films is such that the flexural rigidity, which is defined by (Eh.sup.3)/(12(1.sup.2)), is below 4000 N.Math.m, where E is Young's modulus of the flexible heating part measured according to ASTM D790-03 standard, h is a thickness of the flexible heating part, and is Poisson's ratio of a constituent material of the flexible heating part.

6. The urea tank according to claim 5, wherein the flexural rigidity is less than or equal to 1000 N.Math.m.

7. The urea tank according to claim 6, wherein the flexural rigidity is less than or equal to 1 N.Math.m.

8. The urea tank according to claim 2, wherein a flexural rigidity of the flexible films is such that the flexural rigidity, which is defined by (Eh.sup.3)/(12(1.sup.2)), is below 4000 N.Math.m, where E is Young's modulus of the flexible heating part measured according to ASTM D790-03 standard, h is a thickness of the flexible heating part, and is Poisson's ratio of a constituent material of the flexible heating part.

9. The urea tank according to claim 8, wherein the flexural rigidity is less than or equal to 1000 N.Math.m.

10. The urea tank according to claim 9, wherein the flexural rigidity is less than or equal to 1 N.Math.m.

11. The urea tank according to claim 3, wherein a flexural rigidity of the flexible films is such that the flexural rigidity, which is defined by (Eh.sup.3)/(12(1.sup.2)), is below 4000 N.Math.m, where E is Young's modulus of the flexible heating part measured according to ASTM D790-03 standard, h is a thickness of the flexible heating part, and is Poisson's ratio of a constituent material of the flexible heating part.

12. The urea tank according to claim 11, wherein the flexural rigidity is less than or equal to 1000 N.Math.m.

13. The urea tank according to claim 12, wherein the flexural rigidity is less than or equal to 1 N.Math.m.

14. The urea tank according to claim 1, wherein the flexible heater comprises a plurality of resistive tracks connected in parallel in order to form a capacitive gauge to measure a level of urea in the tank.

15. The urea tank according to claim 2, wherein the flexible heater comprises a plurality of resistive tracks connected in parallel.

16. The urea tank according to claim 3, wherein the flexible heater comprises a plurality of resistive tracks connected in parallel.

17. The urea tank according to claim 1, wherein an interior of the tank is sealed from an exterior by a base plate mounted on one end of the support.

18. The urea tank according to claim 17, wherein the base plate further includes a delivery tube through which urea is supplied.

19. A urea tank comprising: an integrated heating element comprising at least one flexible heating part which is a flexible heater comprising at least one resistive track placed between two flexible films made of plastic, wherein the flexible heater comprises a body and at least one excrescence that extends from the body and is equipped with at least one part of the resistive track, wherein an interior of the tank is sealed from an exterior by a base plate mounted adjacent the flexible heater, and wherein the flexible heater is located inside the urea tank such that the body is submerged in the urea when the tank is full.

Description

(1) The present invention is illustrated nonlimitingly by the appended FIGS. 1 to 4.

(2) FIG. 1 consists of a 3-dimensional view of a base plate with a flexible heater illustrating several variants of the invention.

(3) FIG. 2 consists of a 3-dimensional view of another base plate with a flexible heater also illustrating several variants of the invention.

(4) FIG. 3 consists of two 3-dimensional views of a base plate with a flexible heater according to yet another variant of the invention. In FIG. 3b, the urea trap has been deliberately erased in order to see the shape of the heater in it.

(5) FIG. 4 illustrates a top view and two cross sections through this same base plate.

(6) In the figures identical numbers denote identical or similar components.

(7) The base plate (1) illustrated in FIG. 1 integrates a flexible heater (2) comprising a body (3) fixed to the inside of a support (4) using clips (5) and tentacles (6) connected to the body (3) and having a free end capable of extending inside a urea tank (not represented).

(8) The support (4) of the heater (2) comprises openings (7) that make it possible to create convection loops and to allow the free end of the tentacles (6) to pass through.

(9) The heater comprises a tab (8) intended to be in permanent contact with the upper wall of the tank to create a shaft through the cap (layer) of ice as explained previously.

(10) It also comprises a tentacle (6) specially sized to be able to be inserted into a delivery tube (9) for connection to the urea injection system (not represented).

(11) The base plate (1) incorporates a gauge (10) for measuring the level of urea in the tank, and also other accessories which do not appear clearly in this figure, such as a temperature sensor, a filter, etc.

(12) One of them is firmly attached at its end to a tube (11) connected to a venturi (not represented) and enabling liquid to be sucked up outside of the support (4) in order to fill the latter. In this variant, the support (4) is free from orifices and acts as a liquid (urea) trap.

(13) The base plate (1) illustrated in FIGS. 3 and 4 is, on the other hand, a base plate intended to seal an orifice in the upper wall of a tank. For this purpose it is equipped with a screw thread (1) (visible in the cross sections from FIG. 4) able to cooperate with a complementary screw thread on an excrescence of the tank.

(14) This base plate (1) also incorporates a support (4) for a flexible heater (2) acting as a urea trap. This support (4) is attached to the base plate (as can be seen in the cross sections from FIG. 4) and is pinned to the bottom of the tank by at least one spring (not represented).

(15) The heater (2) is attached to the base plate (1) and to the bottom of the support (4).

(16) The flexibility of the heater (2) enables it to adapt to the various compression ratios of the spring that depend on the distance between the top and bottom of the tank.