System for supplying a liquid for a vehicle and integrated pump/filter module

Abstract

A supply system for a liquid includes a liquid tank, a supply line, a pump, a filter, and a device that makes it possible to purge the line, pump, and filter. The supply system further includes a non-return device preventing liquid from entering into these elements once they have been purged. In this system, the pump, filter and non-return device are combined in a compact module. The filter at least partly surrounds the pump. The non-return device is an integral part of a common housing that surrounds the filter and at least one part of the pump.

Claims

1. A supply system for supplying urea comprising: a urea tank, a line to supply urea, a urea pump, a filter, and a mechanism to purge the line, the urea pump, and the filter and that comprises a non-return device including a bell/siphon combination and preventing urea from entering into the line, the urea pump, and the filter once they have been purged, wherein the urea pump, the filter, and the non-return device are combined in a compact module, the compact module comprising a common housing that surrounds the filter and at least one part of the urea pump, the non-return device being an integral part of the common housing.

2. The supply system according to claim 1, wherein the urea pump sucks up through the filter.

3. The supply system according to claim 1, wherein the non-return device comprises a siphon part of geometry such that once the line, the urea pump and the filter have been purged and filled with gas, this part only allows flow of liquid from the urea tank to the line, the urea pump and the filter when the urea pump is started up.

4. The supply system according to claim 1, wherein the housing has at least in part a geometry such that the housing acts as the non-return device.

5. The supply system according to claim 1, wherein the non-return device is placed at a point for sucking up the liquid in the tank.

6. The supply system according to claim 1, wherein the urea pump is a rotary pump comprising a rotation axle attached both to a mechanical pumping element and a magnetized rotor, the magnetized rotor comprising at least one recess through which fluid sucked up by the mechanical pumping element is forced; and wherein the filter surrounds at least the mechanical pumping element.

7. The supply system according to claim 6, wherein the mechanical pumping element comprises at least two gears, and wherein a purge is carried out by reversing a rotational direction of the pump.

8. The supply system according to claim 6, wherein the pump comprises a stator and electronic cards wherein the common housing comprises a cover and a lower part, and wherein: the lower part comprises a sealed enclosure which comprises the rotor, the stator and the electronic cards, and on which the filter rests; and the cover surrounds the filter and the mechanical element and is attached via a screw and nut connection to the sealed enclosure.

9. The supply system according to claim 8, wherein the cover has a shape of a bell having at least one opening in the lower part, and wherein it is positioned so as to create an annular cavity between an inner surface and an outer surface of the enclosure/filter where the liquid is able to be sucked up through a lower opening.

10. A method for the pollution control of nitrogen oxides (NO.sub.x) from vehicle exhaust gases, comprising utilizing the supply system according to claim 1 in a selective catalytic reduction (SCR) system for the selective catalytic reduction of the NOx in the exhaust gases of a vehicle using a eutectic water/urea solution.

11. A module for a supply system for supplying urea comprising: a line to supply urea, a urea pump, a filter, and a mechanism to purge the line, the urea pump and the filter and that comprises a non-return device including a bell/siphon combination and preventing urea from entering into the line, the urea pump, and the filter once they have been purged, wherein the urea pump, the filter and the non-return device are combined in a compact module, the compact module comprising a common housing that surrounds the filter and at least one part of the urea pump, the non-return device being an integral part of the common housing.

12. A liquid tank comprising a submerged base plate that integrates the module according to claim 11, wherein the common housing comprises a cover and a lower part, and wherein: the lower part consists of a sealed enclosure which comprises a substantially cylindrical wall equipped with a base and molded from one part with the base plate and also a cover assembled in a sealed manner with this cylindrical wall, on which the filter rests and through which the rotation axle is inserted in a sealed manner; and the cover surrounds the filter and the mechanical element and is attached via a screw and nut connection to the sealed enclosure.

Description

(1) The present invention is illustrated, non-limitingly, by FIGS. 1 and 2.

(2) FIG. 1 consists of a cut through a plane parallel to the rotation axle in a pump according to one advantageous variant of the invention and intended to inject a urea solution into the exhaust gases of a diesel vehicle. FIG. 2 consists of a detail of certain elements illustrated in FIG. 1 (in particular of the rotor (6) and of its support (5)).

(3) In these figures, identical numbers denote identical components.

(4) The pump which is illustrated in FIG. 1 comprises a bell-shaped cover (1) surrounding a gear system (2) itself surrounded by a filter (3).

(5) It also comprises a lower sealed enclosure (4) made up of a cover and a cylindrical wall equipped with a base and moulded from one part with a base plate (10) submerged in a urea tank (18). This base plate also comprises a urea trap (11) moulded from one part with it, and also a tube (12), also moulded from one part with it and intended to be connected to a line (20) for supplying urea to the exhaust gases of an engine.

(6) The lower enclosure (4) comprises a magnetized rotor made up of a magnet (6) equipped with an internal support (5) and being contained in a housing (8) that comprises a hollow shaft inserted, in a leaktight manner, into the tube (12). This housing is attached to the cover of the enclosure (4) by an annular attachment part (13) and it is surrounded by magnetic coils (7). Operation of the pump is managed by a controller comprising electronic cards (9) also contained in the sealed enclosure (4).

(7) The geometry of the magnet (6) and of its support (5) is illustrated in detail in FIG. 2 which shows, first, these two elements taken separately and assembled (upper view) and then the support (5) taken alone (lower view). It can be seen that the support (5) has the shape of a sort of stopper comprising a cap (14), a hollow inner cylindrical part (15) intended for receiving the rotation axle and fins (16) that have a substantially helical lateral surface. The edges of these fins define an outer cylindrical wall equipped with substantially helical recesses. This geometry gives the flow of urea inside the support (5), a sort of screw profile which makes it possible to accelerate it and by doing so increase the effectiveness of the pump.