container

Abstract

Container (10), comprising a container body (12) for receiving a liquid, preferably an operating fluid for a vehicle, and a level sensing arrangement (18) for sensing a level of the liquid in the container body (12), characterized in that the container (10) comprises a liquid property determination arrangement (20) for determining a property of the liquid in the container body (12) that is different from the level sensing arrangement (18), wherein the liquid property determination arrangement (20) has an electrical impedance that varies depending on the property of the liquid to be determined, and that the level sensing arrangement (18) comprises at least two level sensing electrodes (22F) and / or the liquid property determination arrangement (20) comprises at least two liquid property determination electrodes (22E).wherein the level sensing electrodes (22F) and / or the liquid property determination electrodes (22E) are at least partially, preferably completely, wettable by the liquid and wherein the liquid property determination arrangement (20) has an impedance device configured to detect the impedance between the at least two liquid property determination electrodes (22E) and to determine the property of the liquid on the basis of the detected impedance, wherein the liquid property determination electrodes (22E) are arranged completely below a lower detection end (36) of the level sensing electrodes (22F) on the container body (12).

Description

[0001] The present invention relates to a container comprising a container body for receiving a liquid, preferably an operating fluid for a vehicle, and a level detection arrangement for detecting a level of the liquid in the container body.

[0002] Such a container is known, for example, from German patent application DE 10 2006 005 529 A1. This container has a level sensing arrangement designed as an electrically conductive electrode device, wherein the electrode device comprises two electrodes made of conductive plastic, each of which can be wetted by liquid in the container body. Depending on the degree of wetting of the electrodes, which is dependent on the fill level, the measured electrical resistance between the two electrodes changes. Thus, the fill level can be determined from the electrical resistance measured between the electrodes.

[0003] A problem with this measuring setup, however, is that the electrical resistance measured between the two electrodes depends not only on the fill level but also on the specific composition of the liquid, which can influence its electrical conductivity. Therefore, if a liquid currently contained in the container has a different conductivity than that of a calibration fluid used to establish a relationship between electrical resistance and fill level, the electrical resistance measured at a given fill level will deviate from the value determined during calibration. The level sensing system thus potentially provides an inaccurate fill level reading. Precise level measurement in a liquid container, especially one for a vehicle's operating fluid, is crucial for safety and environmental protection.As a purely illustrative example, consider exhaust aftertreatment systems for vehicles in which a urea-water solution is injected into the vehicle's exhaust system, where it is converted into ammonia, which is then used to reduce nitrogen oxides. If the level measurement of the urea-water solution in a corresponding storage container is inaccurate—for example, because the urea-to-water ratio deviates from the ratio of a calibration fluid used to calibrate the level measurement device—it is possible that the solution will be completely depleted without the driver being notified in time that a certain minimum level has been reached.As a consequence, it may not be possible to provide a means for reducing nitrogen oxides, resulting in the exhaust gas emitted by the vehicle in question having an undesirably high nitrogen oxide content.

[0004] It is therefore the object of the present invention to provide a container in which the fill level of a liquid contained therein can be precisely detected.

[0005] According to the invention, this problem is solved by a container defined at the outset, which comprises a liquid property determination arrangement different from the level detection arrangement for determining a property of the liquid in the container body that is different from the level, wherein the liquid property determination arrangement has an electrical impedance that varies depending on the property of the liquid to be determined.

[0006] The property in question could, for example, be the composition of the liquid, which has a direct influence on the electrical and dielectric properties of the liquid and can therefore affect the impedance of the liquid property determination setup.

[0007] By providing a liquid property determination device separate from the level sensing device, it is possible to verify whether the liquid whose level is to be measured possesses a predefined property, such as that defined by the properties of a calibration fluid used to calibrate the level sensing device. The liquid property determination device thus allows for verification of a level value detected by the level sensing device. If the property determined by the liquid property determination device deviates from the predefined property, it can be assumed that the level sensing device is not providing sufficiently accurate level values. If the container is installed in a vehicle, a message can be generated in such a case to inform the driver of this situation.

[0008] Alternatively, the level sensing system can be calibrated using various calibration fluids that differ in terms of the fluid property that can be determined by the fluid property measurement system. During operation, calibration data associated with the measured property can then be accessed, allowing correct level values ​​to be determined even for fluids with different properties.

[0009] In principle, the property determined by the liquid property detection system can also be used independently of the fill level measurement, for example, when determining the injection quantity of a urea-water solution to be injected into the exhaust system of a vehicle, which must be adjusted depending on the urea-water ratio to achieve a specific reduction effect. Since this ratio influences the electrical impedance of the liquid property detection system and can therefore be detected by it, a signal from the liquid property detection system reflecting this ratio can be used to determine the amount of urea-water to be injected.

[0010] In a further development of the invention, it can be provided that the level detection arrangement comprises at least two level detection electrodes and / or the liquid property determination arrangement comprises at least two liquid property determination electrodes, wherein the level detection electrodes and / or the liquid property determination electrodes are at least partially, preferably completely, wettable by the liquid.

[0011] In a level sensing arrangement comprising at least two level sensing electrodes, the level can be determined by measuring the electrical impedance between the at least two electrodes. This means that moving components, such as floats, can be dispensed with, which generally have the disadvantage that they cannot precisely follow the actual level due to deposits, for example, thus limiting the level sensing accuracy.

[0012] A liquid property measurement arrangement comprising at least two liquid property measurement electrodes allows for the local measurement of a specific liquid property, for example, in the area of ​​a container outlet. This enables, for instance, the precise dosing of a urea-water solution to be injected into the exhaust system of a vehicle. Similarly, it is conceivable to provide multiple liquid property measurement electrodes at multiple positions within the container body to determine the location dependency of the property to be measured.

[0013] Furthermore, direct contact between the liquid on the one hand and level-sensing electrodes and / or liquid property determination electrodes on the other ensures high measurement accuracy, since, unlike non-contact measurement methods which generally rely on the reflection and transmission properties of the liquid, the influence of geometric factors, such as the specific geometry of the container body, is eliminated. These can represent a significant source of error in measurement methods based on reflection and transmission measurements.

[0014] Furthermore, it may be provided that at least two level detection electrodes and / or at least two liquid property determination electrodes are designed in a plate-like shape or with a round, approximately oval, in particular circular cross-section.

[0015] In this context, "plate-shaped" means that the extent of each electrode in two mutually orthogonal directions is greater than the extent in a third orthogonal direction. Therefore, two plate-shaped electrodes can be arranged relative to each other in such a way that they adopt a parallel-plate capacitor-like configuration. This enables the generation of a locally well-defined electric field and thus precise level detection and / or precise determination of the liquid properties or the fill level.

[0016] In a further development of the invention, it can be provided that the level sensing electrodes have a principal extension direction that is essentially orthogonal to the liquid surface. This allows the level sensing electrodes to be designed with a smaller dimension in the principal extension direction than level sensing electrodes whose principal extension direction forms an angle other than 90° with the liquid surface, in order to detect the same level range.

[0017] Alternatively or additionally, the liquid property detection electrodes can be provided with a main direction of extension that is essentially parallel to the liquid surface. In this configuration, the liquid property detection electrodes remain essentially unchanged up to a predetermined fill level, preferably completely wetted by the liquid, so that the signal output by the liquid property detection arrangement up to this fill level essentially only reflects the liquid property and is therefore not distorted by a degree of wetting of the liquid property detection electrodes that changes over the operating cycle.

[0018] In a further development of the invention, it can be ensured that both liquid property determination electrodes are completely wetted up to a predetermined fill level by ensuring that the spacing direction of at least two of the liquid property determination electrodes is essentially parallel to the liquid surface.

[0019] In order to ensure a wetting state of the liquid property determination electrodes that is as constant as possible over the operating range of the level detection electrodes, and in order to thereby ensure a precise determination of the liquid property during a detection operation of the level detection arrangement, a further development of the invention may provide that the liquid property determination electrodes are arranged completely below an upper detection end, preferably below a lower detection end, of the level detection electrodes on the container body.

[0020] In a further development of the invention, it can be provided that the level sensing electrodes and / or the liquid property determination electrodes are at least partially, preferably completely, made of conductive plastic. Level sensing electrodes and / or liquid property determination electrodes made of conductive plastic can be easily manufactured by injection molding. If the container body is also made of plastic, the manufacture of the container body and the electrodes can be carried out essentially simultaneously.

[0021] Alternatively or additionally, the level sensing electrodes and / or the liquid property determination electrodes can be designed at least partially, preferably completely, as metallic strip-shaped layers. This design allows for a highly space-saving construction and also offers the possibility of mounting both the level sensing electrodes and the liquid property determination electrodes on a common substrate, on which additional components, such as heating elements, can also be provided if required. Thin-film technology offers a particularly simple and precise manufacturing process for the level sensing electrodes and / or liquid property determination electrodes designed according to this further development.

[0022] Furthermore, it can be provided that the level detection arrangement and the liquid property determination arrangement are essentially identical in design. This makes the manufacture of a container according to the invention particularly simple, since only a single basic detection unit needs to be provided, which, through a suitable arrangement within the container body and, if necessary, through appropriately adapted reading devices, can be used as a level detection arrangement or a liquid property determination arrangement.

[0023] The present invention will be explained in more detail below with reference to the accompanying figure. This shows a perspective view of a container according to the invention.

[0024] In the figure, a container is represented in a general way by the reference symbol. 10 equipped. This includes a container body. 12for holding a liquid. This liquid can be a vehicle operating fluid, such as windshield washer fluid or a urea-water solution injected into an exhaust manifold to reduce nitrogen oxides in the exhaust gas. The liquid can be supplied via a [missing information] on the container body. 12 designated entrance 14 filled and via an outlet 16 from the container body 12 can be taken.

[0025] The container 10 also includes a level detection system 18 to detect the fill level of the liquid in the container body 12 as well as a liquid properties determination order 20 to determine a property of the liquid in the container body that differs from the fill level 12The property in question could be, for example, the composition of the liquid, such as the ratio of urea to water in a urea-water solution. The liquid property determination setup 20 The electrical impedance of the liquid varies depending on the property being determined. This behavior of the electrical impedance serves as the basis for determining the liquid property, whereby a relationship between the liquid property and the electrical impedance of the liquid property determination setup can be established by calibration using one or more calibration liquids with predefined, well-defined properties.

[0026] As shown in the figure, the level detection arrangement can be 18 two level sensing electrodes 22F and the liquid property determination order 20two fluid property determination electrodes 22E exhibiting features that are completely wettable by the liquid. Both the level sensing electrodes 22F as well as the fluid property determination electrodes 22E As shown in the figure, contact sections can each be 24 , 26 exhibiting which originate from a respective electrode 22F , 22E through a suitable wall 28 , 30 of the container body 12 are led to the outside so that they can be connected to a corresponding readout unit (not shown in the figure). One of these is located inside the container body. 12 running area 32 of the contact section 24 can be electrically insulated from the liquid to allow level sensing by the level sensing arrangement 18cannot be influenced. The fill level is therefore between one of the vertical positions of the upper edges. 34 the level sensing electrodes 22F corresponding maximum fill level L100 of 100% and one of the vertical positions of lower edges 36 the level sensing electrodes 22F corresponding minimum fill level L0 of 0% from the fill level detection arrangement 18 measurable.

[0027] The level sensing electrodes 22F and the fluid property determination electrodes 22E They can be designed in a plate-like shape, as shown in the figure, and arranged opposite each other in such a way that the level detection arrangement 18 and the liquid property determination order 20Each has a plate capacitor-like configuration. This enables the generation of a locally well-defined electric field and therefore precise level measurement or a precise determination of the liquid properties.

[0028] The level sensing electrodes 22F can be attached to the container body in this way 12 The level sensing electrodes must be arranged so that their main extension direction RF is essentially orthogonal to the liquid surface F. This allows the level sensing electrodes to detect the same level range. 22F They are designed with a smaller dimension in the main extension direction RF than level detection electrodes whose main extension direction encloses an angle other than 90° with the liquid surface.

[0029] The fluid property determination electrodes 22E can be attached to the container body in this way 12The electrodes must be arranged so that their main direction of extension RE runs essentially parallel to the liquid surface F. This ensures that the liquid property determination electrodes 22E up to a predetermined fill level, they are essentially constantly, preferably completely, wetted by the liquid, regardless of this level, so that the liquid property determination arrangement 20 The signal output up to this fill level essentially reflects only the liquid property and is therefore not distorted by a change in the degree of wetting over an operating cycle. This is because both liquid property detection electrodes... 22E By ensuring that the fluid properties determination electrodes are completely wetted up to this specified fill level, it can be guaranteed that the spacing direction RA is correct. 22E essentially parallel to the liquid surface F.

[0030] As long as the fluid property determination electrodes 22E are completely wetted by the liquid, which can be detected by the level detection arrangement. 22F The delivered signal must always be checked. Therefore, to ensure very precise level measurement, it is advantageous if the liquid property determination electrodes 22E such a container body 12 are arranged so that they are completely wetted by liquid below a fill level L50 of 50%, preferably below a fill level L25 of 25%.

[0031] The positioning of the liquid property determination electrodes shown in the figure 22E However, the liquid property determination electrodes are particularly preferred. 22Eare arranged in such a way that they are completely wetted up to the detectable minimum fill level L0 of 0% and thus are usable by all the level detection arrangement 18 Detectable fill levels allow for verification of the liquid properties.

[0032] The level sensing electrodes 22F or / and the fluid property determination electrodes 22E They can be made at least partially from conductive plastic. Level sensing electrodes made from conductive plastic 22F and / or fluid property determination electrodes 22E can be easily manufactured by injection molding. (The container body is also made of plastic.) 12 can the production of container bodies 12 and electrodes 22F , 22E essentially happening simultaneously.

[0033] Alternatively or additionally, the level detection electrodes can be used 22F or / and the fluid property determination electrodes 22E at least partially designed as flexible, strip-shaped metallic layers. This design allows for a highly space-saving construction and also offers the possibility of integrating both the level sensing electrodes. 22F as well as the fluid property determination electrodes 22E to be provided on a common carrier, on which additional components, such as heating elements, can also be provided if required. Particularly simple and precise manufacturing of such level-sensing electrodes. 22F and / or fluid property determination electrodes 22E Thin-film technology offers this.

[0034] As shown in the figure, the level detection arrangement 18 and the liquid property determination order 20They are essentially built identically. This allows for the manufacturing of the container. 10 This can be made particularly simple, as only a single basic detection unit needs to be provided, which is arranged appropriately within the container body. 12 and, if necessary, by appropriately adapted reading devices as a level detection arrangement 18 or liquid property determination order 20 can be used.

[0035] In the present embodiment, the function of the liquid property determination arrangement was 20 only with regard to a review of the level monitoring order 18 The delivered fill level is described. The liquid property determination order 20However, the determined liquid property can also be used independently of the fill level measurement, for example to determine a flow rate from the container body depending on the determined property. 12 To determine the amount of liquid to be extracted. As a purely illustrative example, consider a container for holding a urea-water solution. The urea-water ratio influences both the level measurement and the reduction effect of the nitrogen oxides in a vehicle's exhaust gas produced by this solution through the ammonia it generates. Therefore, to achieve a specific reduction effect, a quantity of urea-water solution adapted to the urea-water ratio must be injected. Information about the urea-water ratio can be obtained from the liquid property determination system. 20 can be obtained. QUOTES INCLUDED IN THE DESCRIPTION

[0036] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0037] DE 102006005529 A1

[0002]

Claims

[1] Container ( 10 ), comprising a container body ( 12 ) for receiving a liquid, preferably an operating fluid for a vehicle, and a level detection arrangement ( 18 ) to detect the fill level of the liquid in the container body ( 12 ), characterized by that the container ( 10 ) one of the level detection arrangement ( 18 ) various liquid property determination arrangements ( 20 ) to determine a property of the liquid in the container body that differs from the fill level ( 12 ) includes the liquid property determination arrangement ( 20 ) exhibits an electrical impedance that varies depending on the property of the liquid to be determined. [2] Container ( 10 ) according to claim 1, characterized by that the level detection arrangement ( 18 ) at least two level sensing electrodes ( 22F) includes and / or the liquid property determination order ( 20 ) at least two fluid property determination electrodes ( 22E ) includes the level sensing electrodes ( 22F ) or / and the fluid property determination electrodes ( 22E ) are at least partially, preferably completely, wettable by the liquid. [3] Container ( 10 ) according to claim 2, characterized by that at least two level sensing electrodes ( 22F ) or / and at least two liquid property determination electrodes ( 22E ) are plate-shaped or have a round, approximately oval, or especially circular cross-section. [4] Container ( 10 ) according to claim 2 or 3, characterized by that the level detection electrodes ( 22F) have a principal extension direction (RF) that is essentially orthogonal to the liquid surface (F) and / or the liquid property determination electrodes ( 22E ) have a principal extension direction (RE) that is essentially parallel to the liquid surface (F). [5] Container ( 10 ) according to claim 4, characterized by that the spacing direction (RA) of at least two liquid property determination electrodes ( 22E ) is essentially parallel to the liquid surface (F). [6] Container ( 10 ) according to one of claims 2 to 5, characterized by that the fluid property determination electrodes ( 22E ) completely below an upper detection limit ( 34 ), preferably completely below a lower detection end ( 36 ), the level detection electrodes ( 22F ) on the container body ( 12 are arranged. [7] Container ( 10) according to any one of claims 2 to 6, characterized by that the level detection electrodes ( 22F ) or / and the fluid property determination electrodes ( 22E ) are made at least partially, preferably completely, of conductive plastic. [8] Container ( 10 ) according to any one of claims 2 to 7, characterized by that the level detection electrodes ( 22F ) or / and the fluid property determination electrodes ( 22E ) at least partially, preferably completely, are formed as metallic strip-shaped layers, preferably produced using thin-film technology. [9] Container ( 10 ) according to any of the preceding claims, characterized by that the level detection arrangement ( 18 ) and the liquid property determination order ( 20 ) are essentially identical in structure.

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