EP2964956A1

EP2964956A1 - Pump for metering a liquid additive for a selective catalytic reduction device

Info

Publication number: EP2964956A1
Application number: EP14702289.1A
Authority: EP
Inventors: Rolf BRÜCK; Jan Hodgson
Original assignee: Continental Automotive GmbH
Current assignee: Continental Automotive GmbH
Priority date: 2013-03-05
Filing date: 2014-02-04
Publication date: 2016-01-13
Also published as: US20160032914A1; WO2014135325A1; DE102013102129A1; JP2016513767A; CN105121851A; KR20150122777A; CN105121851B; US10054116B2

Abstract

The invention relates to a pump (1) for conveying a liquid, comprising a pump housing (2) that has at least one inlet (3) and at least one outlet (4), an eccentric element (5) being rotatably arranged in said pump housing (2) and surrounded by a deformable membrane (6), said deformable membrane (6) and pump housing (2) delimiting at least one conveyor path (7) from the at least one inlet (3) to the at least one outlet (4) and forming at least one seal (8) for the conveyor path (7), and said seal (8) being able to be displaced along the conveyor path (7) by a movement (9) of the eccentric element (5). Between the eccentric element (5) and the deformable membrane (6), a spring layer (10) is arranged by means of which said eccentric element (5) and deformable membrane (6) are tensioned relative to one another.

Description

PUMP FOR DOSING A LIQUID ADDITIVE FOR A SELECTIVE CATALYTIC REDUCTION DEVICE

The invention relates to a pump for conveying a liquid. For example, the pump may be used in a motor vehicle to deliver a liquid additive to an exhaust treatment device.

In motor vehicles exhaust treatment devices are common, in which the exhaust gases of an internal combustion engine are cleaned with the aid of a liquid additive. An exhaust gas purification method performed in such exhaust treatment devices is the selective catalytic reduction method [SCR method; SCR = Selective Catalytic Reduction]. In this process, nitrogen oxide compounds in the exhaust gas are reduced to harmless substances with the aid of a reducing agent. As a reducing agent usually ammonia is used. Ammonia is often not directly supplied to an exhaust treatment device. Rather, the exhaust treatment device, a liquid additive is supplied, which is converted in the exhaust gas to ammonia. Such a liquid additive is also referred to as a reducing agent precursor solution. The reaction of the liquid additive in the exhaust gas treatment device takes place thermally (due to the heat of the exhaust gases) and / or hydrolytically (assisted by a hydrolysis catalyst). As a liquid additive for the SCR process, urea-water solution is widely used. A 32.5 percent urea-water solution is available under the trade name AdBlue®. The pump described here is particularly suitable for the promotion and provision of such liquid additive.

A pump for delivering and providing a liquid additive can usually also perform a metering function. By a metering function, it is meant that the pump specifically promotes and provides a quantity of the liquid additive predetermined by a control unit. The accuracy with which the actual amount of liquid additive speaks, is crucial for successful exhaust gas purification in the exhaust treatment device. If too much liquid additive is provided, ammonia may escape from the exhaust treatment device. If too little liquid additive is provided, the nitrogen oxide compounds in the exhaust gas are not fully reacted. The pump should therefore allow the most accurate possible dosage. A high dosing accuracy should also be achieved regardless of the aging of the pump during the entire life of the pump. In pumps for promoting and providing the described liquid additives is also problematic that the liquid additives can freeze. For example, the urea-water solution described above freezes at -11 ° C. Such low temperatures can occur in motor vehicles, for example, during long periods of inactivity in winter. Upon freezing, a volume expansion of the liquid additive occurs. This volume expansion can damage or even destroy the pump. The pump should therefore be designed freeze-resistant, so that a volume expansion of the liquid additive can be added without the pump being damaged or destroyed.

On this basis, it is an object of the present invention to solve the problems described in connection with the prior art or at least alleviate. In particular, a particularly advantageous pump for conveying a liquid is described, which on the one hand is freeze-resistant and, moreover, has a high accuracy in the metering of the liquid additive, the influence of the aging of the pump on the accuracy of the metering being low.

These objects are achieved with a pump according to the features of Pa tentanspruchs 1. Further advantageous embodiments of the pump are in the from pending patent claims. The features listed individually in the patent claims can be combined with one another in any technologically meaningful manner and can be supplemented by explanatory facts from the description, wherein further embodiments of the invention are shown.

According to the invention, a pump for conveying a liquid has a pump housing with at least one inlet and at least one outlet. In the pump housing, an eccentric is rotatably disposed, which is surrounded by a deformable diaphragm, wherein the deformable diaphragm and the pump housing define at least one conveying path from the at least one inlet to the at least one outlet and form at least one seal of the conveying path, wherein the Seal is displaceable by a movement of the eccentric along the conveying path. Between the eccentric and the deformable membrane, a spring layer is arranged, with which the eccentric and the deformable membrane are braced against each other.

The pump is particularly suitable for conveying one of the above-described liquid additives for exhaust gas purification and at the same time providing it precisely metered.

The pump housing is preferably shaped like a flat cylinder or a flat ring. The term "flat" here means in particular that the diameter of the pump housing is greater than the height of the pump housing. Through the pump housing extends an axis. The eccentric is fixed against rotation on this axis. When the axle is rotated, the eccentric rotates in the pump housing. The eccentric is thus rotatable relative to the pump housing. Preferably, exactly one inlet and one outlet exist. The inlet and the outlet are preferably arranged on a peripheral surface of the pump housing. If below from the peripheral surface and / or the end faces of the pump housing is mentioned, hereby each of the respective inner surfaces (to the interior of the pump housing facing surfaces) of the pump housing meant. The deformable diaphragm preferably forms an annular member which is disposed about the eccentric and between the eccentric and the pump housing. The deformable diaphragm and the pump housing form a continuous fluid-tight delivery path extending from the inlet to the outlet. The delivery path may be considered as an annular channel between the wall of the housing and the deformable membrane. By the term "fluid-tight" is meant here that the deformable membrane is sealed to the housing so that no liquid can pass into the conveying path except via the inlet and the outlet. For this purpose, the deformable membrane is preferably partially fluid-tight against the housing. It is additionally possible that the deformable membrane is connected in sections to the housing. The deformable membrane may also be glued to the housing. The connection of the deformable membrane with the housing is in particular designed such that the conveying path formed as an annular channel is not interrupted by the connection. The deformable membrane may, for example, be bent around a peripheral surface of the pump housing and adhesively bonded to the housing in an edge region of the deformable membrane. It is also possible that the deformable membrane rests in a fluid-tight manner on two mutually opposite end faces of the housing. Preferably, the eccentric is arranged so that the deformable membrane is deformed or grooved when the eccentric is rotated. The eccentric pushes the deformable membrane at least at one point against the housing and in particular against a peripheral surface of the housing. As a result, the deformable membrane contacts the housing and in particular the peripheral surface of the housing at this point, so that a seal is formed. The seal is fluid-tight and therefore not passable for the liquid in the conveying path. At the seal so the delivery is interrupted. When turning the eccentric and the resulting deformation of the membrane, the seal is moved. When the eccentric is rotated in a direction of rotation corresponding to a conveying direction from the inlet to the outlet, the seal along the conveying path is shifted from the inlet to the outlet. As a result, the liquid is sucked from the inlet into the conveying path. At the same time, the liquid is forced out of the conveying path through the outlet.

Between the deformable diaphragm and the eccentric is a spring position. By a spring layer is meant in particular an annular layer which separates the deformable membrane from the eccentric and at the same time forms a contact means from the eccentric to the deformable membrane. Thus, that the spring position between the eccentric and the deformable membrane is braced, in particular means that the spring position is compressed by the deformable membrane and the eccentric. The eccentric and the deformable membrane put the spring layer under a compressive stress. The spring position transmits a force exerted by the eccentric force on the deformable membrane, so that on the one hand, the conveying path is formed from the inlet to the outlet and also the at least one seal of the conveying path exists.

Preferably, the deformable membrane during rotation of the eccentric also at least partially compressed (in particular in the region of the seal). Thus, the deformable membrane and the spring layer together form a spring system between the housing and the eccentric, which is zusammengewalkt during the rotation of the eccentric.

The spring position between the deformable membrane and the eccentric has the effect of reducing the forces acting on the deformable membrane and / or even. The forces acting on the deformable membrane are greatest in the region of the at least one seal, because the deformable membrane is pressed against the housing there. The spring position distributes the force acting at the position of the seal evenly.

As a particular embodiment of the spring position, means for clamping the deformable membrane can also be provided on the eccentric itself. These means can also be integrated in the eccentric. The eccentric may, for example, have at least one spring-mounted section which clamps the deformable membrane. The at least one resiliently mounted portion may for example be designed as a cam, which is displaceably mounted in a receptacle of the eccentric and which is pressed for bracing by a spring element against the deformable membrane. It can be arranged on the eccentric several such recordings, spring elements and cams. By a plurality of such receptacles, spring elements and cams uniform clamping of the deformable membrane can be achieved.

The pump described allows a very accurate metering of the liquid. The rotation of the eccentric promotes the liquid. The delivered amount of liquid is dependent on the angle of rotation or the rotational speed of the eccentric. In a particularly preferred embodiment, even at least in sections, there is a linear relationship between the angle of rotation and the delivered quantity. The term "sections" here means in particular that this linear relationship exists only in the region of certain positions of the at least one seal within the housing. For example, the linear relationship does not exist if the at least one seal passes over the inlet or outlet of the pump. Another advantage of the pump described is the high resistance to a volume expansion of the liquid, which can occur in a freezing situation. Due to the high flexibility of the spring position and the deformable diaphragm, the pump can absorb a volume expansion in the case of freezing and will not be damaged.

Furthermore, the pump is advantageous if a sealing means is provided between the outlet and the inlet, which prevents a flow of the liquid additive from the outlet to the inlet against a conveying direction.

The (freestanding) sealing means can be realized for example by a local thickening or stiffening of the deformable membrane. It is also possible that the sealing means is formed by a nose in the pump housing, which locally reduces the distance between the eccentric and the pump housing at the location between the outlet and the inlet. By such a nose or such a thickening of the deformable membrane, it can be ensured that the deformable membrane always bears directly against the pump housing at the position between the outlet and the inlet, thus forming a fluid-tight, immovable seal between the pump housing and the deformable membrane , Such a sealant makes it possible to prevent backflow of liquid additive within the pump. This can improve the efficiency and efficiency of the pump. Furthermore, a pump is advantageous if the deformable diaphragm has a first spring constant in a radial direction starting from an axis of rotation of the eccentric, and the spring position has a second spring constant in this radial direction, the second spring constant being smaller than the first spring constant. The spring constant indicates which force is necessary to compress the deformable diaphragm or the spring position. The spring contant is given here in Newtons per square centimeter of membrane area per centimeter path length, whereby the path length designates the path around which the deformable membrane or the spring position is compressed. The force which is necessary to compress the spring position is therefore preferably smaller than the force necessary to compress the deformable membrane. This causes the spring layer to compensate for irregularities in flexibility and / or thickness of the deformable membrane. For example, if the deformable membrane is made of uneven thickness, then the spring layer deforms between the deformable membrane and the eccentric so as to compensate for the irregularities in the thickness of the deformable membrane. This reduces the manufacturing tolerances that must be maintained in the manufacture of a pump described.

Furthermore, the pump described is advantageous if the deformable membrane is made of a polymer material which can swell under the action of the liquid, so that at least one thickness or a spring constant of the deformable membrane changes in the radial direction.

In particular, in the case that the liquid is a liquid additive for exhaust gas purification, the liquid will penetrate into the deformable membrane and thereby change the thickness or the spring constant of the deformable membrane. This process takes a relatively long time, so that it occurs during the use of a described pump in a motor vehicle over time or increasingly amplified over time.

The spring layer is preferably set up such that it is subject to only a slight change due to aging in comparison to the deformable membrane. In the case that the deformable membrane by swelling thicker, the spring layer in the areas where the deformable membrane has become thicker, simply compressed further. This is particularly readily possible if the spring constant of the spring layer is smaller compared to the spring constant of the deformable membrane.

The membrane can also change by aging, regardless of the pumped liquid. The deformable membrane is typically made of a crosslinked polymeric material. Such a material continues to crosslink over time, increasing the stiffness of the deformable membrane. Such a change in the deformable membrane can also be compensated by the spring position. If the spring constant of the deformable membrane decreases as a result of aging, then the deformation of the deformable membrane is simply increasingly replaced by the deformability or the compressibility of the spring layer.

Furthermore, the pump is advantageous if a sealing layer is arranged between the deformable membrane and the spring layer, which prevents penetration of the liquid from the deformable membrane into the spring position. Such a sealing layer may for example be formed by a fluid-tight insert which lies between the spring layer and the deformable membrane. This fluid-tight insert is preferably fluid-tightly connected to the pump housing, so that no liquid can penetrate past the sealable layer of the deformable membrane in the spring position. A sealing layer can effectively protect the spring layer from the liquid. This is particularly advantageous if in the spring position by the liquid also an aging and / or a change could occur. Furthermore, the pump is advantageous if the spring layer comprises a plurality of spring elements which are clamped between the deformable membrane and the eccentric. The spring elements in the spring position are aligned in a radial direction from an axis of rotation of the eccentric, so as to compress the deformable diaphragm from the eccentric towards the pump housing. Each individual spring element has a spring constant. These spring constants of the spring elements define the spring constant of the spring position in the radial direction. The structure of the spring layer with a plurality of spring elements allows a particularly individual construction of the spring position. For example, it is possible to change individual spring elements when they have aged. In addition, the spring constant of the spring position can be increased or decreased in sections by the individual spring elements are selected accordingly. It can therefore find different spring elements use within a pump.

Furthermore, the pump is advantageous if the spring layer comprises an elastic material which is clamped between the deformable membrane and the eccentric. The elastic material is compressible under the action of a force and therefore has a spring constant.

The elastic material may be, for example, a fabric or a foam and comprise a metallic material or a polymer material. If the elastic material is a foam, then this foam is preferably open-pored so that gas inclusions within the foam do not affect the compressibility of the foam. The elastic material allows the spring position particularly simple and inexpensive to manufacture. Furthermore, the pump is advantageous if the eccentric has an outer bearing ring and an inner eccentric portion, wherein between the inner eccentric portion and the outer bearing ring at least one bearing is arranged, with which a rotational movement of the inner eccentric portion can be converted into an eccentric wobbling movement of the outer bearing ring ,

The inner eccentric is fixed against rotation on an axis of the pump. This axis is connected to a drive motor of the pump. Through the axis of the inner eccentric section is driven. The outer bearing ring is preferably in contact with the spring layer. The bearing allows implementation of the rotational movement of the eccentric on the outer bearing ring. By dividing the eccentric in an inner eccentric and an outer bearing ring with an interposed bearing thrust forces can be avoided, which would arise if the eccentric would be directly rotatable and the rotational movement of the eccentric would act directly on the spring position or the deformable membrane. As a result, the torque required for driving the eccentric is considerably reduced. The bearing may be a ball bearing or a roller bearing. But preferred is a roller bearing, because a roller bearing for the power transmission from the eccentric portion on the outer bearing ring is particularly suitable.

The invention finds particular application in a motor vehicle, comprising an internal combustion engine, an exhaust gas treatment device for cleaning the exhaust gases of the internal combustion engine and a tank in which a liquid for exhaust gas purification is stored, wherein the liquid can be conveyed by a pump described from the tank to the exhaust gas treatment device.

The liquid is preferably a liquid additive for exhaust gas purification. In the exhaust gas treatment device, an SCR catalyst is preferably provided. see at which nitrogen oxide compounds in the exhaust gas of the internal combustion engine with the aid of the liquid additive can be reduced to harmless substances. The tank and the exhaust gas treatment device are preferably connected to one another via a line. The line opens via an injector in the exhaust treatment device. With the injector, a discharge of the liquid can be carried out in the exhaust gas treatment device. The pump is arranged on the line so that the liquid additive can be sucked from the tank by the pump and conveyed via the line to the injector.

The invention and the technical environment will be explained in more detail with reference to FIGS. The figures show preferred embodiments, to which the invention is not limited. In particular, it should be noted that the figures and in particular the illustrated proportions are only schematic. Show it:

1 shows a pump of the prior art,

2 shows a variant of the described pump,

3 shows a further embodiment of the described pump,

4 shows still another embodiment variant of the pump described, FIG. 5 shows a section through a variant of the described pump,

6 shows a section through a further embodiment of the described pump, Fig. 7: a simplified three-dimensional representation of the pump described, and

Fig. 8: a motor vehicle, comprising a described pump.

Some of the features of a pump 1 shown in FIGS. 1 to 6 will be explained here together first. The pump 1 has a pump housing 2 with a circumferential surface 31. An inlet 3 and an outlet 4 open into the pump housing 2 through the peripheral surface 31. Preferably, the pump housing 2 moreover has two end faces 30, which delimit the pump housing 2 in the axial direction. In the pump housing 2, an eccentric 5 is arranged, which is surrounded by a deformable membrane 6. Between the pump housing 2 and the eccentric 5 there is a conveying path 7 from the inlet 3 to the outlet 4. The conveying path 7 is passable from the inlet 3 to the outlet 4 for the liquid, but the conveying path 7 is interrupted at one point on which a seal 8 is formed. The seal 8 is formed in that the deformable membrane 6 fluid-tight against the pump housing 2 and on the peripheral surface 31 of the pump housing 2. By a rotation of the eccentric 5 about an axis of rotation 12, the deformable membrane 6 is deformed and the seal 8 is displaced along the conveying path 7 from the inlet 3 to the outlet 4. This results in a delivery of liquid along a conveying direction 19 from the inlet 3 to the outlet 4. Between the outlet 4 and the inlet 3, a sealing means 14 is provided, which together with the deformable membrane 6, a stationary seal 33 between the deformable membrane. 6 and the pump housing 2 is formed, which is not displaced even during a rotational movement of the eccentric 5 and prevents a backflow of the liquid from the outlet 4 to the inlet 3. Viewed in a radial direction 11, starting from the rotational axis 12 of the pump, the deformable membrane 6 has a thickness 13. This thickness 13 is changed in certain regions during the rotation of the eccentric 5 in that the deformable membrane 6 is compressed. This happens, for example, in the region of the seal 8, where the deformable membrane 6 against the pump housing 2 is pressed. The eccentric 5 preferably consists of an inner eccentric portion 18 which is rotatable and connected to the axis 25 of a drive motor 24 of the pump 1. The axis 25 is preferably located in the axis of rotation 12. In addition, the eccentric 5 preferably consists of an outer bearing ring 17, which is separated by the bearing 26 of the inner eccentric portion 18. By the bearing 26, a rotational movement of the inner eccentric portion 18 is converted into an eccentric wobbling movement of the outer bearing ring 17. This eccentric tumbling motion is transmitted to the deformable membrane 6 to move the seal 8. In the embodiment of a pump 1 in Fig. 1, the deformable membrane 6 is applied to the eccentric 5 and on the outer bearing ring 17 of the eccentric 5. Between the deformable membrane 6 and the eccentric 5 no spring position is arranged. The embodiment of a pump according to FIG. 1 is therefore not the subject of the invention.

2, a spring layer 10 is arranged between the eccentric 5 and the outer bearing ring 17 of the eccentric 5 and the deformable diaphragm 6, which is braced there. This spring layer 10 is constructed from a plurality of spring elements 15 and has a spring layer thickness 32 in the radial direction 11.

In a second embodiment of the described pump 1 according to FIG. 3, there also exists a spring layer 10 between the deformable membrane 6 and the eccentric 5. However, the spring layer 10 is formed here from an elastic material 16 and moreover with respect to the deformable membrane 6 Help sealing layer 35 sealed so that no liquid can penetrate from the deformable membrane 6 in the spring layer 10. In the third embodiment of a described pump 1 according to FIG. 4, spring elements 15 are themselves formed on the eccentric 5 as a spring position, which has at least one section of the eccentric 5 designed as a cam 36 against the eccentric 5 deform deformable membrane 6. The cam 36 and the spring element 15 are each arranged in a receptacle on the eccentric 5. The division of the eccentric 5 on an inner eccentric portion 18 and an outer bearing ring 17 with an interposed bearing 26 is not shown in the embodiment of FIG. 4. However, these features may be added to the embodiment of FIG. 4. For example, FIG. 5 shows the pump 1 shown in FIG. 2 in a cutting direction (see arrows in FIG. 2). It can be seen that the conveying path 7 has a different cross-sectional area on the two sides of the pump 1 shown in FIG. This different cross-sectional area of the conveying path 7 results from the eccentricity of the eccentric 5, which displaces the deformable membrane 6 within the pump housing 2 such that the cross section of the conveying path 7 changes regularly and a seal (not shown in FIG. 5) along the conveying path 7 is shifted from the inlet to the outlet. The deformable membrane 6 is fluid-tight against the end faces 30 of the housing. In Fig. 5, the axis 25 with the drive motor 24 can be seen, which drives the eccentric 5 of the pump 1.

FIG. 6 shows a sectional view corresponding to FIG. 5 of a pump 1. The housing 2 is here free of end faces and has only one peripheral surface 31. The deformable membrane 6 is bent around the peripheral surface 31 of the housing 2 and with its edge regions 34 with the housing 2. prevented. Thus, a particularly fluid-tight connection of the deformable membrane 6 to the housing 2 is made possible.

7 shows a schematic representation of a pump 1 with a pump housing 2 with inlet 3 and outlet 4 in an isometric view. Evident are the axis of rotation 12 and the radial direction 11. The axis 25 for driving the eccentric, not shown within the pump housing 2 and the drive motor 24 are also shown. Fig. 8 shows a motor vehicle 20, comprising an internal combustion engine 21 and an exhaust treatment device 22 for cleaning the exhaust gases of the combustion engine 21. The motor vehicle 20 also has a tank 23 in which a liquid for exhaust gas purification (in particular urea-water solution) stored is. This liquid can be conveyed via a line 28 by means of a pump 1 to an injector 27. With the injector 27, the liquid of the exhaust treatment device 22 can be supplied. In the exhaust gas treatment apparatus 22, an SCR catalyst 29 is provided, with which the method of selective catalytic reduction for purifying the exhaust gases of the combustion engine 21 can be performed.

The pump described allows a particularly precise dose delivery of liquid to an exhaust treatment device in a motor vehicle. The pump is subject only to a very small change in the metering due to aging of the pump and is also freezing. LIST OF REFERENCE NUMBERS

1 pump

2 pump housings

3 inlet s

4 outlet

5 eccentrics

6 deformable membrane

7 funding route

8 sealing

9 exercise

10 spring position

11 radial direction

12 rotation axis

13 membrane thickness

14 sealant

15 spring element

16 elastic material

17 outer situation

18 inner eccentric section

19 conveying direction

20 motor vehicle

21 internal combustion engine

22 exhaust treatment device

23 tank

24 drive motor

25 axis

26 bearings

27 injector

28 line SCR catalyst

face

peripheral surface

Spring layer thickness immovable sealing edge area

sealing layer

cam

admission

Claims

claims

Pump (1) for conveying a liquid having a pump housing (2) with at least one inlet (3) and at least one outlet (4), wherein in the pump housing (2) an eccentric (5) is rotatably arranged, of a deformable Diaphragm (6) is surrounded, wherein the deformable membrane (6) and the pump housing (2) delimit at least one delivery path (7) from the at least one inlet (3) to the at least one outlet (4) and at least one seal (8). form the conveying path (7), wherein the seal (8) by a movement (9) of the eccentric (5) along the conveying path (7) is displaceable, wherein between the eccentric (5) and the deformable membrane (6) has a spring position ( 10) is arranged, with which the eccentric (5) and the deformable membrane (6) are braced against each other.

Pump (1) according to claim 1, wherein between the outlet (4) and the inlet (3) a sealing means (14) is provided, the flow of the liquid additive from the outlet (4) to the inlet (3) against a conveying direction (19) prevented.

Pump (1) according to one of the preceding claims, wherein the deformable diaphragm (6) in a radial direction (11) starting from a rotation axis (12) of the eccentric (5) has a first spring constant and the spring layer (10) in this radial direction (11) has a second spring constant, the second spring constant being less than the first spring constant.

Pump (1) according to one of the preceding claims, wherein the deformable membrane (6) is made of a polymer material which can swell under the action of the liquid, so that at least one thickness (13) or a spring constant of the deformable membrane (6) changed in the radial direction.

Pump (1) according to one of the preceding claims, wherein between the deformable membrane (6) and the spring layer (10) a sealing layer (35) is arranged, which is a penetration of the liquid from the deformable membrane (6) into the spring layer (10). prevented.

Pump (1) according to one of the preceding claims, wherein the spring layer (10) comprises a plurality of spring elements (15) which are clamped between the deformable membrane (6) and the eccentric (5).

Pump (1) according to one of the preceding claims, wherein the spring layer (10) comprises an elastic material (16) that is clamped between the deformable membrane (6) and the eccentric (5).

Pump (1) according to one of the preceding claims, wherein the eccentric (5) has an outer bearing ring (17) and an inner eccentric section (18), wherein between the inner eccentric section (18) and the outer bearing ring (17) at least one bearing ( 26) is arranged, with which a rotational movement of the inner eccentric portion (18) in an eccentric wobbling movement of the outer bearing ring (17) can be implemented.

A motor vehicle (20) comprising an internal combustion engine (21), an exhaust treatment device (22) for cleaning the exhaust gases of the combustion engine (21) and a tank (23) in which a liquid is stored for exhaust gas purification, wherein the liquid with a pump (1 ) according to one of the preceding claims from the tank (23) to the exhaust gas treatment device (22) can be promoted.