EXTRUDED FLUID SENSOR FOR IMPEDANCE-BASED ACQUISITION OF A QUANTITY OR A QUALITY OF A FLUID SURROUNDING THE SENSOR

Abstract

A fluid sensor for impedance-based determination of a quantity or a quality, such as type, composition, or purity of a fluid present in the surroundings of the fluid sensor, where the fluid sensor includes a first electrically conductive electrode which is arranged on a first extruded substrate component made of an electrically insulating, thermally curable synthetic, and where the fluid sensor includes a second electrically conductive electrode which is arranged on a second extruded substrate component made of an electrically insulating, thermally curable synthetic, where in each case an electrically conductive surface both that of the first electrode and also of the second electrode is exposed in such a way that it is wettable by fluid in the surroundings of the fluid sensor.

Claims

1-15. (canceled)

16. A fluid sensor for impedance-based determination of a quantity or a quality, such as type, composition, or purity, of a fluid present in the surroundings of the fluid sensor, where the fluid sensor comprises a first electrically conductive electrode which is arranged on a first extruded substrate component made of an electrically insulating, thermally curable synthetic, and where the fluid sensor comprises a second electrically conductive electrode, which is arranged on a second extruded substrate component made of an electrically insulating, thermally curable synthetic, where in each case an electrically conductive surface both that of the first electrode and also of the second electrode is exposed in such a way that it is wettable by fluid in the surroundings of the fluid sensor.

17. The fluid sensor according to claim 16, wherein the first and/or the second electrode are formed from a metal strip proceeding along an extrusion direction of the substrate component carrying them.

18. The fluid sensor according to claim 16, wherein the first and/or the second electrode are formed from a material strip made of a thermoplastic synthetic filled with electrically conductive material that is coextruded together with the substrate component carrying them and therefore that is proceeding along an extrusion direction of the substrate component carrying them.

19. The fluid sensor according to claim 18, wherein the at least one coextruded electrode exhibits between 40% by weight and 70% by weight electrically conducting filling material.

20. The fluid sensor according to claim 19, wherein the electrically conductive filling material comprises or is an electrically conductive powder.

21. The fluid sensor according to claim 18, wherein the electrically conductive filling material comprises or is an electrically conductive powder.

22. The fluid sensor according to claim 21, wherein the electrically conductive filling material comprises a graphite powder.

23. The fluid sensor according to claim 16, wherein the first and the second electrode are arranged with wettable electrically conductive surfaces facing towards one another.

24. The fluid sensor according to claim 23, wherein the two wettable electrically conductive surfaces facing towards one another of the first and the second electrode are parallel to one another.

25. The fluid sensor according to claim 16, wherein the first and the second substrate component are different sections of an integrally extruded substrate arrangement.

26. The fluid sensor according to claim 25, wherein the substrate arrangement, when viewing a sectional plane orthogonal to an extrusion direction, exhibits two flanks connected with one another, of which each carries one electrode, respectively.

27. The fluid sensor according to claim 26, wherein the flanks of the substrate arrangement at least section-wise are parallel to one another and are connected to one another by a base section of the substrate arrangement.

28. The fluid sensor according to claim 18, wherein the fluid sensor exhibits an electrically conducting connector component pushed into, pressed into, or screwed into the thermoplastic synthetic filled with electrically conductive material.

29. A fluid sensor arrangement with a sensor carrier which carries a fluid sensor according to claim 16 configured as a fluid level sensor and/or a fluid quality sensor.

30. The fluid sensor arrangement according to claim 29, wherein the sensor carrier includes an electric or electronic switching circuit module for inducing a temporally varying current in an electrode of a fluid sensor and/or for measuring a temporally varying current in the other electrode respectively of the fluid sensor.

31. A method for manufacturing a fluid sensor according to claim 16, comprising the following steps: Extrusion of a thermally curable synthetic as a substrate component, Simultaneous feeding of an electrically conductive electrode to the extruded substrate component, and Bonding of the substrate component and the electrode with one another.

32. The method according to claim 31, wherein the step of the simultaneous feeding of the electrically conductive electrode comprises: Feeding a metal tape from a metal tape reservoir, where the feeding speed corresponds to the extrusion speed, or Coextruding a thermally curable synthetic filled with electrically conductive filling material as the electrically conductive electrode together with the extrusion of the substrate component.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The invention may take physical form in certain parts and arrangement of parts, a preferred embodiment of which will be described in detail and illustrated in the accompanying drawings which forms a part hereof and wherein:

[0041] FIG. 1 A tank in schematic part cross-section with a fluid sensor arrangement with a fluid sensor according to the invention when viewed in the direction of the arrow I of FIG. 2,

[0042] FIG. 2 The tank of FIG. 1 in schematic part cross-section when viewed in the direction of the arrow II of FIG. 1,

[0043] FIG. 3 A schematic perspective view of the fluid sensor arrangement of FIGS. 1 and 2,

[0044] FIG. 4A A rough schematic front view of a connector component pushed into an extruded electrode, and

[0045] FIG. 4B A rough schematic side view of the connector component of FIG. 4A pushed into an extruded electrode.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0046] Referring now to the drawings wherein the showings are for the purpose of illustrating preferred and alternative embodiments of the invention only and not for the purpose of limiting the same, in FIG. 1, a liquid tank for accommodating an operating fluid on a vehicle is denoted generally by 10. The tank 10 exhibits a tank wall 12 which confines a tank volume 14 inside the tank 10 towards the outside.

[0047] The tank 10 can be blow-molded from a thermoplastic synthetic or it can be joined together from several injection-molded tank shells. In the latter case too, the tank wall 12 is formed from a thermoplastic synthetic.

[0048] A line 16 in FIG. 1 indicates the maximum filling height up to which liquid can be accommodated in the tank volume 14 of the tank 10.

[0049] At the tank wall 12, more precisely at the tank bottom 18, there is accommodated a fluid sensor arrangement 20, with a sensor carrier 22 which carries a fluid level sensor 24 and a fluid quality sensor 26 which is more clearly discernible in FIG. 3.

[0050] The fluid level sensor 24 extends from the sensor carrier 22 up to approximately the maximum filling height indicated by the line 16, such that the length of the fluid level sensor 24 wetted by the liquid accommodated in the tank volume 14 corresponds approximately for all filling quantities properly accommodated in the tank 10 to the respective current filling height of the liquid in the tank volume 14 or is a linear-proportional function of same.

[0051] The fluid quality sensor 26 is constructed identically to the fluid level sensor 24. Merely the extension length of the fluid quality sensor 26 along the extrusion axis E of the fluid sensors 24 and 26 is significantly shorter in the fluid quality sensor 26 than in the fluid level sensor 24. The fluid quality sensor 26 protrudes for a short distance from the sensor carrier 22 in such a way that other than in the case of complete emptying of the tank 10, for most liquid quantities accommodated in the tank volume 14 the fluid quality sensor 26 is completely immersed in the respectively accommodated liquid quantity.

[0052] From each of the fluid sensors 24 and 26 there is emitted a signal that depends on the impedance of the respective fluid sensor and on the liquid wetting it. Since the wetting situation of the fluid level sensor 24 depends on the level of the liquid quantity 14 filled in the tank 10, the fluid level sensor 24 emits a signal that depends on the level in the tank 10.

[0053] Since in the great majority of cases in which liquid is accommodated in the tank volume 14 of the tank 10, the fluid quality sensor 26 is completely wetted by the accommodated liquid, the fluid quality sensor 26 emits, as long as a minimum quantity of liquid is accommodated in the tank 10, an acquisition signal which depends only on the accommodated liquid itself, for instance on its electric conductance. Therefore, the signal of the fluid quality sensor 26 can be used to determine the purity and/or the type and/or the composition of the liquid accommodated in the tank 10, for instance by comparing the signal emitted by the fluid quality sensor 26 with reference signals which are stored in a data memory of a control device, for example in a control device 27, and to which there is matched there corresponding information through previous calibration.

[0054] With the quality information obtained through the signals of the fluid quality sensor 26, it can not only possible to determine whether the tank is filled with operating fluid intended for storage by the tank or whether there is erroneous filling, but also whether the filled correct operating fluid is sufficient clean and free from undesirable contamination. The signals of the fluid quality sensor 26 can, furthermore, be utilized for increasing the accuracy of the filling level measurement by the fluid level sensor 24, whose signals in addition to the filling height of the liquid in the tank volume 14 also depend on the quality of the filled liquid.

[0055] The fluid sensors 24 and 26 are coextruded as bar material, namely along the extrusion axis E. During the coextrusion of the electrodes 36 and 38 and of the substrate arrangement 28, the extruded bar material leaves the extrusion matrix along the extrusion axis E as a quasi-endless material. After the extrusion, the bar material is cut to the required individual lengths for the fluid sensors 24 and 26.

[0056] Since the fluid sensors 24 and 26 are formed from the same extruded bar material, there suffices hereinafter the description of only one fluid sensor, which also applies to the other fluid sensor. Because of the easier recognizability, hereinafter the larger fluid level sensor 24 shall be described in further detail.

[0057] In the view shown in FIG. 1, one looks sideways at the substrate arrangement 28 of the fluid level sensor 24.

[0058] The direction of view towards the tank 10 is rotated by approximately 90° in FIG. 2. One is looking not sideways at the U-shaped substrate arrangement 28 of the fluid sensor 24, but rather one is looking parallel to the flanks 30 and 32 towards the base section 34 of the substrate arrangement 28 which connects the flanks 30 and 32.

[0059] On the sides facing towards each other of the flanks 30 and 32, which are substrate components in accordance with the above descriptive introduction, there is arranged on each an electrically conductive electrode 36 or 38 respectively with electrically conductive exposed surfaces 36a and 38a through coextrusion with the substrate arrangement 28.

[0060] The substrate arrangement 28 and the electrodes 36 and 38 comprise the same thermoplastic synthetic, for example polypropylene, such that when extruded together they can be firmly bonded with one another without problems. In the present embodiment example, the synthetic of the electrodes 36 and 38 is preferably filled with graphite powder, namely with a quantity fraction of 40% to 60% by weight.

[0061] FIG. 3 depicts the fluid sensor arrangement 20 in a schematic perspective view of improved depth of detail compared with FIGS. 1 and 2. Since, as already explained above, the fluid sensors 24 and 26 are formed starting from the same extruded bar material, identical sections of the extruded bar material of the fluid quality sensor 26 are provided with the same reference labels as the already elucidated sections of the exposed bar material of the fluid level sensor 24.

[0062] The fluid sensors 24 and 26 are inserted into the sensor carrier 22 in recesses which exhibit a complementary contour to the fluid sensors 24 and 26. The fluid sensors 24 and 26 are preferably firmly bonded with the sensor carrier 22, for instance by gluing or welding. The gap formed between the fluid sensors 24 and 26 and the recesses in the sensor carrier 22 can be sealed with a sealant 40. The course of the sealant 40 shows the course of the gap formed between the fluid sensors 24 and 26 on the one hand and the recesses in the sensor carrier 22 accommodating them on the other. The fluid sensors 24 and 26 completely penetrate through the sensor carrier 22 in the thickness direction, such that the electrodes 36 and 38 are accessible from outside the tank 10.

[0063] At the sensor carrier 22 there is arranged on the side facing towards the tank volume, towards which the viewer of FIG. 3 looks, a temperature sensor 42 which measures the temperature of the operating fluid accommodated in the tank volume 14 and relays it to a control device.

[0064] The sensor carrier 22 exhibits an overlap surface 44, which overlaps fluid-tight with the tank wall 12 in the fully assembled state of the tank with an intermediate arrangement of a seal or of fluidically applied and then cured sealing material.

[0065] The arrangement region of the fluid sensors 24 and 26 and of the temperature sensor 42 is bordered by a collar 44 projecting into the tank volume 14.

[0066] In order to stiffen the fluid sensors 24 and 26, in particular the longer fluid level sensor 24, stiffening ribs 46 and 48 are configured at the outer surfaces of the substrate arrangement 28 not occupied by electrodes. The stiffening ribs 46 and the marginal stiffening ribs 48 at the free longitudinal end of the parallel flanks 30 and 32 of the U-shaped substrate arrangement 28 are produced integrally with the rest of the substrate arrangement during extrusion.

[0067] FIGS. 4A and 4B show a connector component 50, whose anchor section 52 is pushed into the electrodes 36 and 38, in the depicted example into the electrode 36.

[0068] The anchor section 52 exhibits a tip 54, which due to its wedge action facilitates the pushing of the anchor section 52 into the electrode 36. Sawtooth formations 56 on both sides of the essentially even anchor section 52 and overall even connector component 50 serve as pull-out protection against pulling the connector component 50 out of the electrode 36.

[0069] Outside the electrode 36 there remains a connector section 58 to which an electrical conductor can be connected, for instance by soldering or by pushing on a contact shoe.

[0070] FIG. 4B shows that the connector component 50 depicted as an example is a flat connector component, i.e. it exhibits a significantly smaller thickness dimension than a length and width dimension.

[0071] Instead of a pushed-in or pressed-in connector component, a connector component can also be driven rotationally into, in particular screwed into, an electrode.

[0072] In the sensor carrier 22 there can be accommodated the aforementioned control device 27 (s. FIG. 2), which corresponds to the electronic switching circuit module mentioned in the descriptive introduction. It can be connected with the electrodes 36 and 38 so as to allow signal transmission and feed a current into one of the two electrodes and/or acquire and process a current signal from at least one of the two electrodes or relay it to a higher-level control device.

[0073] While considerable emphasis has been placed on the preferred embodiments of the invention illustrated and described herein, it will be appreciated that other embodiments, and equivalences thereof, can be made and that many changes can be made in the preferred embodiments without departing from the principles of the invention. Furthermore, the embodiments described above can be combined to form yet other embodiments of the invention of this application. Accordingly, it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation.