Unit for feeding a reducing solution from the tank to the exhaust duct of an engine

Abstract

Unit (11) for feeding a reducing solution from the tank to the exhaust duct of an endothermic engine is provided. The unit comprises a supporting head (13) arranged for being associated to an aperture provided in a reducing solution tank and a heating device (15) for heating the reducing solution contained in the tank. The heating device (15) extends from the supporting head (13) and is provided with a duct (17) for a heating fluid. The duct (17) is defined by a side wall (31) which, when the unit (11) is in use, is internally in contact with the heating fluid passing through the duct (17) and externally in contact with the reducing solution present in the tank. At least one portion of the wall (31) of the duct (17) is non-smooth inside and/or outside the duct.

Claims

1. A unit (11) for feeding a reducing solution tank of a vehicle equipped with an endothermic engine, said unit being for feeding a reducing solution from the tank to an exhaust duct of the endothermic engine, said unit comprising a supporting head (13) firmly associated to an aperture of the reducing solution tank and a heating device (15) for heating the reducing solution contained in the tank, the heating device (15) extending longitudinally from the supporting head (13) and being provided with a duct (17) for a heating fluid, said duct (17) being defined by a side wall (31) which, when the unit (11) is in use, is internally in contact with the heating fluid passing through the duct (17) and externally in contact with the reducing solution present in the tank, wherein said duct (17) has a circular cross-section and comprises a forward section in which a rectilinear portion (21a) and a horseshoe-shaped portion (21c) are defined, and a rectilinear return section (23), said rectilinear portion (21a) and return section (23) having axes that are mutually parallel and said horseshoe-shaped portion (21c) extending on a plane that is substantially perpendicular to the parallel axes of the rectilinear portion (21a) and of the return section (23) of the duct (17), wherein the side wall (31) of each of the rectilinear portion (21a) and return section (23) of the duct (17) is corrugated inside and outside and comprises a plurality of ridges (33) and valleys (35), wherein the ridges (33) and the valleys (35) are oriented perpendicularly to the flow of the heating fluid circulating in the duct (17), annularly continuous, mutually alternated and regularly distributed both inside and outside the duct, and the horseshoe-shaped portion (21c) of the duct (17) is smooth.

2. The unit according to claim 1, wherein the side wall (31) of each of the rectilinear portion (21a) and return section (23) of the duct (17) is corrugated, so as to cause a turbulent motion in the heating fluid flowing through the duct (17) and to increase the thermal exchange surface with respect to both the fluid flowing inside the duct and the reducing solution surrounding it.

3. The unit according to claim 2, wherein an inner cross-section of the duct (17) at the ridges (33) is about 5-10% greater than an inner cross-section of the duct (17) at the valleys (35).

4. The unit according to claim 3, wherein the head has a disk like shape and comprises means for fixing the unit (11) to the tank, wherein, when the unit (11) is mounted in the reducing solution tank, said duct (17) is in hydraulic connection with the outside of the tank through openings (13b,13c) provided in the head (13) and equipped with connectors for connection to a cooling circuit of the endothermic engine, said duct (17) being isolated from the tank by means of the head (13), wherein the duct (17) forms a closed path and wherein the unit (11) further comprises a tube (25) for taking the reducing solution out of the tank in which said solution is contained, a temperature sensor (27), and a level sensor (29).

5. The unit according to claim 4, wherein said means for fixing the unit (11) to the tank comprise radial spring clips (13a).

6. The unit according to claim 5, wherein said head (13) is made of plastic material.

7. The unit according to claim 4, wherein said head (13) is made of plastic material.

8. The unit according to claim 2, wherein the head has a disk like shape and comprises means for fixing the unit (11) to the tank, wherein, when the unit (11) is mounted in the reducing solution tank, said duct (17) is in hydraulic connection with the outside of the tank through openings (13b,13c) provided in the head (13) and equipped with connectors for connection to a cooling circuit of the endothermic engine, said duct (17) being isolated from the tank by means of the head (13), wherein the duct (17) forms a closed path and wherein the unit (11) further comprises a tube (25) for taking the reducing solution out of the tank in which said solution is contained, a temperature sensor (27), and a level sensor (29).

9. The unit according to claim 8, wherein said means for fixing the unit (11) to the tank comprise radial spring clips (13a).

10. The unit according to claim 9, wherein said head (13) is made of plastic material.

11. The unit according to claim 8, wherein said head (13) is made of plastic material.

12. The unit according to claim 1, wherein an inner cross-section of the duct (17) at the ridges (33) is about 5-10% greater than an inner cross-section of the duct (17) at the valleys (35).

13. The unit according to claim 1, wherein the head has a disk like shape and comprises means for fixing the unit (11) to the tank, wherein, when the unit (11) is mounted in the reducing solution tank, said duct (17) is in hydraulic connection with the outside of the tank through openings (13b,13c) provided in the head (13) and equipped with connectors for connection to a cooling circuit of the endothermic engine, said duct (17) being isolated from the tank by means of the head (13), wherein the duct (17) forms a closed path and wherein the unit (11) further comprises a tube (25) for taking the reducing solution out of the tank in which said solution is contained, a temperature sensor (27), and a level sensor (29).

14. The unit according to claim 13, wherein said means for fixing the unit (11) to the tank comprise radial spring clips (13a).

15. The unit according to claim 14, wherein said head (13) is made of plastic material.

16. The unit according to claim 13, wherein said head (13) is made of plastic material.

17. A vehicle comprising an endothermic engine having an exhaust duct, a reducing agent tank, and the unit (11) according to claim 1 for feeding a reducing agent solution from the tank to the exhaust duct of the endothermic engine.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Some preferred embodiments and variants of the invention will be described below by way of non-limiting example with reference to the annexed drawings, in which:

(2) FIG. 1A is a perspective view of the feeding unit according to the invention, with the heating duct partially removed;

(3) FIG. 1B is an enlarged view of a portion of the unit of FIG. 1A;

(4) FIG. 2A is a perspective view of the heating duct;

(5) FIG. 2B is an enlarged view of a portion of the heating duct;

(6) FIG. 3A is a side view of a portion of the heating duct of the unit of FIG. 1, in a first embodiment;

(7) FIG. 3B is a longitudinal sectional view of the duct of FIG. 3A;

(8) FIG. 4 is a longitudinal sectional view of the heating duct, in a second embodiment of the unit according to the invention;

(9) FIG. 5 is a cross-section of a portion of the heating duct of the unit of FIG. 1, in a third embodiment;

(10) FIG. 6 is a perspective view of the heating duct in a variant.

DESCRIPTION OF SOME PREFERRED EMBODIMENTS OF THE INVENTION

(11) In the drawings, same or functionally equivalent parts are designated with the same referenced numerals.

(12) Referring to FIGS. 1A and 1B, there is illustrated a unit 11 for feeding a reducing solution from the tank to the exhaust of an I.C. engine, according to a preferred embodiment of the invention. The unit 11 comprises a supporting head 13. The head 13 is arranged for being firmly associated to an aperture provided in a reducing solution tank. In the example shown, the head 13 has a disk-like shape. The head 13 allows fixing of the unit 11 to the tank with conventional methods known to the person skilled in the art, such as by means of radial spring clips 13a. Referring also to FIGS. 2A and 2B, the unit further comprises a heating device 15 for heating the reducing solution contained in the tank. The device 15 extends longitudinally from the supporting head 13 and comprises a duct 17 for a heating fluid. When the unit 11 is mounted in the reducing solution tank, the duct 17 is inside the tank and is at least partially submerged in the reducing solution contained therein.

(13) The duct 17 is firmly associated to the head 13 and is in hydraulic connection with the outside of the tank through openings 13b, 13c provided in the head 13 and equipped with connectors for connection to the cooling circuit of the I.C. engine. The duct 17 is isolated from the tank by means of the head 13, which can preferably be made of a plastic material. The duct 17 which is inside the duct forms a closed path and preferably has a forward section, in which a rectilinear portion 21a and a spiral-like portion 21b are provided, and a rectilinear return section 23. The unit 11 further comprises a tube 25 for taking the reducing solution out of the tank in which said solution is contained, a temperature sensor 27 and a level sensor 29.

(14) Referring to FIGS. 3A and 3B, the wall 31 of the duct 17 is non-smooth inside and outside the duct. When the unit 11 is in use, the wall 31 on its inside is in contact with the heating fluid circulating in the duct 17 and on its outside is in contact with the reducing solution contained in the tank. In the illustrated embodiment the duct 17 has circular cross-section. In addition, still with reference to the illustrated embodiment, the wall 17 is corrugated and comprises a plurality of continuous annular ridges 33 and valleys 35 that are mutually alternated and regularly distributed both inside and outside the duct 17. The ridges 33 and the valleys 35, both being annular, are preferably parallel. Advantageously, with this arrangement, the motion of the heating fluid passing through the duct 17 is turbulent and promotes a better heat exchange with the wall 31 of the duct 17. In addition, the useful surface for the heat exchange between the heating fluid or the reducing solution and the wall 31 of the duct 17 is greater, for a same length, than in the case of an hypothetical duct with smooth wall.

(15) In this embodiment the inner cross-section of the duct 17 at the ridges 33 is about 5-10% greater than the inner cross-section of the duct 17 at the valleys 35.

(16) Referring to FIG. 4, there is illustrated a first variant of the unit 11, in which the wall 31 of the duct 17 comprises a plurality of bosses 37 defining as many ridges 33 and valleys 35 both inside and outside the duct 17. In the example shown, the bosses 37 have a circular base and extend outside the duct 17 so as to form corresponding hemispheres. The bosses 37 are regularly distributed along the wall 31 of the duct 17 and define as a whole a bossed wall 31. In other embodiments the bosses 37 can be distributed in an irregular way.

(17) Referring to FIG. 5, there is illustrated a second variant of the unit 11, in which the wall 31 has a plurality of longitudinal projections 39. In the example shown, the projections 39 have a semi-circular cross-section and define as many ridges 33 and valleys 35 distributed around the duct. The projections 39 are regularly distributed around the duct 17, but irregular projections can be provided in other embodiments. It is apparent that according to this variant the advantage of the invention are partially exploited, as no turbulent motion is substantially generated inside the duct, because the ridges 33 and the valleys 35 are parallel, rather than perpendicular or oblique, to the flow.

(18) Referring to FIG. 6, there is illustrated a variant of the heating duct 17. According to this variant, the duct 17 comprises a forward section, in which a rectilinear portion 21a and a horseshoe-shaped portion 21c are defined, and a rectilinear return section 23. The rectilinear portion 21a and the section 23 have axes that are mutually parallel and the wall 31 that is corrugated inside and outside. Ridges 33 and valleys 35 are therefore defined on said wall 31. The horseshoe-shaped portion 21c is, instead, preferably smooth for simplifying manufacturing. The horseshoe-shaped portion 21c further extends on a plane that is substantially perpendicular to the parallel axes of the portion 21a and of the section 23 of the duct 17.

(19) The invention as described and illustrated may undergo several changes and modifications falling within the same inventive principle.