Title of Invention

PROTECTIVE ELEMENT FOR A PROBE, CORRESPONDING PROBE AND HONEYCOMB ELEMENT

Abstract

The invention relates to a protective element (10) for attachment to a probe (8), especially a probe (8) for use in the exhaust gas system of a motor vehicle, whereby an inner surface (13) of the protective element (10) can at least partially be placed against an outer surface (14) of the probe (8). The protective element (10) comprises an at least temporarily water-binding layer (11) which chemically and/or physically binds water in a first operating state and releases the bound water in a second operating state. The configuration of the water-binding layer (11) of the protective element (10) according to the invention effectively prevents water shock on the probe (8) as water vapor is prevented from condensing out, especially in the cold start phase in the area of the probe (8) having the highest thermal capacity. The water-binding layer (11) temporarily binds the water in one operating state while it releases the water in a second operating state.

Full Text

WO 2006/048192 PCT/EP2005/011561 Protective element for a measuring probe and corresponding measuring probe and honeycomb element The subject matter of the invention is a protective element, in particular for use in the exhaust system of an internal combustion engine for preventing water shock on measuring probes, and a measuring probe having such a protective element and a honeycomb element, in particular a catalytic converter carrier element and/or filter element with such a measuring probe and a corresponding motor vehicle. The preferred field of application is in the exhaust system of a motor vehicle, for example of an automobile or of a motor- operated two-wheeled vehicle. Measuring probes, in particular lambda probes, which are used in the exhaust systems of internal combustion engines, for example in honeycomb elements, are often made inoperative by water shock. Water shock is understood to be the process of wetting of the surface of the measuring probe with fluid water or else the condensing out of water vapor on the surface of the measuring probe. Since a water shock generally leads to irreparable damage or at least to a malfunction of the measuring probe, the present invention is based on the object of specifying measures which reliably prevent the water shock on a measuring probe, and to specify a corresponding measuring probe and honeycomb element as well as a corresponding motor vehicle. This object is achieved by means of a protective element having the features of claim 1, a measuring probe having the features of claim 15, a honeycomb element having the features of claim 21 and a motor vehicle having the features of claim 23., Advantageous WO 2006/048192 - 2 - PCT/EP2005/011561 developments are the subject matter of the respective dependent claims.. In a protective element according to the invention for a measuring probe, the protective element comprises at least one temporarily water-binding layer which in a first operating state binds water chemically and/or physically and in a second operating state releases the bound water. The protective element according to the invention is suitable in particular for a measuring probe for use in the exhaust system of a motor vehicle. The protective element is preferably configured in such a way that an inner surface can be applied at least partially to an outer surface of the measuring probe. When a measuring probe is installed in a honeycomb element such as, for example, a catalytic converter carrier element and/or a filter element, a temperature minimum is also present at the base of the measuring probe particularly in a cold starting phase of an internal combustion engine owing to the exothermic catalytic reaction, said base lying on the outer surface of the honeycomb element, in particular on an outer casing pipe which is formed there. This is due to the maximum thermal capacity which is present there and which brings about relatively slow heating. If the catalytic reaction has then started in parts of the honeycomb element, it is possible for water vapor to form in the interior of the honeycomb element owing to the exothermic character of the reaction. If said water vapor then touches the measuring probe, in particular a lambda probe, water condenses out here, that is to say a water shock occurs, at the coldest point, in particular on the outer surface of the honeycomb element and/or the base of the measuring probe bearing against the outer casing pipe, which base heats up slowly as a result of the relatively high thermal capacity of the outer casing pipe at this point. If a WO 2006/048192 - 3 - PCT/EP2005/011561 protective element according to the invention is then formed here, in particular as an additional component which simply fits snugly over the measuring probe or else is integrally formed onto it, the water-binding layer causes water to be bound temporarily on or in said layer chemically and/or physically by chemisorption or physisorption in the first operating state.. In particular in the case of heated lambda probes, the protective element can also be embodied in such a way that a gap is formed between an inner surface of the protective element and an outer surface of the measuring probe, at least in certain areas. If the measuring probe comprises a measuring sensor, which is for example a corresponding semiconductor component which is surrounded by a protective cap which provides in particular protection against mechanical and/or thermal influences on the measuring sensor, the protective element can also preferably be embodied in such a way that it is formed between the measuring sensor and protective cap. The present chemical and/or physical bonding is reversible by changing into the second operating state. The change into the second operating state can be carried out, for example, by increasing the temperature so that, for example, water adsorbs onto and/or into the water-binding layer at temperatures below a limiting temperature, and desorbs again after the limiting temperature has been exceeded., The protective element is preferably also formed in its entirety from a temporarily water-binding material so that the temporarily water-binding layer forms the entire protective element. The water-binding layer thus acts as a type of sponge in which the water which causes the water shock is at least partially temporarily bound. If a large number of cold starts are carried out one after the other without WO 2006/048192 - 4 - PCT/EP2005/011561 the limiting temperature being exceeded, this would cause the water absorption capacity of the water- binding layer to be exhausted at a specific time. For this reason, an engine management system for the internal combustion engine is particularly advantageous, in particular within the scope of the engine control system of the internal combustion engine of an automobile in which the execution of a plurality of cold starts which do not bring about a change into the second operating state is detected and the composition and/or quantity of the fuel is changed in good time before the water absorption capacity of the water-binding layer is exhausted, with the result that, for example, unburnt hydrocarbons reach the honeycomb element and are burnt there so that the second operating state is reliably brought about. The suitability of the protective element for a measuring probe for use in the exhaust system of a motor vehicle has the result, in particular, that the protective element can withstand the conditions in the exhaust system, in particular the temperatures present there and the temperature transients and/or temperature gradients occurring there, the corresponding gas pressures and/or highly reactive substances as well as mechanical loading and vibrations or impacts. Depending on the design of the protective element it may be suitable for surrounding the measuring probe and/or the measuring sensor completely or else only around part of its circumference, in particular in certain areas. In the latter case, the protective element can be embodied, for example, as a circular ring segment. It is also possible, and in accordance with the invention, to form a plurality of corresponding protective elements which extend around part of the circumference and which together enclose the measuring probe around its entire circumference, in particular in an axial region. WO 2006/048192 - 5 - PCT/EP2005/011561 According to one advantageous development of the invention, the protective element has an essentially closed shape with an inner surface and an outer surface, and in particular the protective element is in the form of a ring and/or circular ring. The protective element may be embodied in particular in an annular fashion as a protective ring. A ring designates in this context in particular a closed structure which matches and/or can be matched in its geometric shape to the geometric shape of a measuring probe, a protective cap and/or a measuring sensor. A ring can consequently not only have a circular ring- shaped geometry but rather, for example, also have the basic shape of a polygon, preferably of a hexagon or quadrilateral, in particular a square or a rectangular or else an ellipse. Any closed, annular structure which has an outer surface and an inner surface is to be considered a ring within the sense of the present invention. According to one advantageous embodiment of the securing ring according to the invention the protective element is at least partially compressible or elastic. When the protective element is embodied as a component which is separate from the measuring probe, this advantageously facilitates the attachment of the protective element to the measuring probe, for example by making it simply fit snugly over the measuring probe. According to a further advantageous embodiment of the securing ring according to the invention, at least the temporarily water-binding layer is porous, and has in particular a porosity of at least 40%, preferably more than 70%. WO 2006/048192 - 6 - PCT/EP2005/011561 The formation of at least the temporarily water-binding layer as a porous structure advantageously increases the surface which is available for chemical and/or physical binding of the water. According to a further advantageous embodiment of the protective element according to the invention, the latter, in particular the water-binding layer, comprises at least one of the following materials: a) mica; b) aluminum oxide, in particular □-aluminum oxide; or c) zeolite, in particular zeolite A, X and/or Y and/or faujasite.. Mica is understood in particular to be silicate materials which crystallize in a monoclinal fashion, for example muscovite, lepidolite, biotite or paragonite. In particular, mica is understood to be materials, which can be represented by means of the following formula: (K, Na, Ca) (Al, Mg, Fe, Li) 2_3 (OH) 2 (Si, A1)4-5O10 where the atoms in brackets can be represented in any desired combination.. The term zeolite is understood to mean both naturally occurring and synthetically manufactured aluminosilicates, in particular also those which have been subjected to at least partial cationic exchange.. Basically however, it is also possible, and in accordance with the invention, to use other materials to construct the water-binding layer if, by means of these materials, water can be bound in a first operating state and released again in a second operating state., The formation of the water-binding layer from a plurality of materials or a plurality of water-binding layers is also possible and in accordance with the invention. WO 2006/048192 - 7 - PCT/EP2005/011561 According to a further advantageous embodiment of the protective element according to the invention, said protective element is temperature resistant at temperatures up to 500°C, preferably 750°C, particularly preferably 1000°C. Such temperature resistance advantageously permits use in the exhaust system of an automobile. According to a further advantageous embodiment of the protective element according to the invention, the first operating state and the second operating state differ in operating temperature. Accordingly, the change from one operating state to the other can be brought about by changing the operating temperature, that is to say the temperature which is present at the protective element. According to a further advantageous embodiment of the protective element according to the invention, the first operating state is present essentially at temperatures below a limiting temperature, in particular a desorption temperature, and the second operating state is present essentially at temperatures above the limiting temperature. This distinguishes in particular the temporary binding of the water by adsorption. Limiting temperature is to be understood here also as a limiting temperature range in which a change in the ratio of adsorption to desorption occurs at or in the water-binding layer. According to a further advantageous embodiment of the protective element according to the invention, the limiting temperature is higher than the boiling temperature of water. WO 2006/048192 - 8 - PCT/EP2005/011561 This effectively prevents water from being released by the water-binding layer and condensing directly out again. In particular, the limiting temperature is higher than 100°C. According to a further advantageous embodiment of the protective element according to the invention, the water-binding layer is located at least partially on a surface of the protective element. According to a further advantageous embodiment of the protective element according to the invention, the water-binding layer is formed at least partially on a surface of the protective element which is at least partially on the outside in relation to the measuring probe and/or in relation to a measuring sensor. The water-binding layer is thus at least not exclusively formed on the inner surface of the protective element and also not exclusively formed on the outer surface of the protective element which in particular bears against the inner surface of the measuring probe wall when the measuring sensor is installed later. This means that the water-binding layer is preferably formed in areas at the surface of the protective element which are in contact with the exhaust gas when said protective element is used, for example, in the honeycomb element. According to a further advantageous embodiment of the protective element according to the invention, the protective element is suitable for essentially gas- tight abutment against the outer surface of the measuring probe and/or of the measuring sensor. According to a further advantageous embodiment of the protective element according to the invention, the WO 2006/048192 - 9 - PCT/EP2005/011561 protective element is suitable for essentially gas- tight abutment against an inner surface of a measuring probe bore. By Virtue Of the suitability for essentially gas-tight abutment against the outer surface of the measuring probe and/or the inner surface of the measuring probe bore, the protective element can also carry out a sealing function, and can, for example, by embodied as a sealing ring. According to a further advantageous embodiment of the protective element according to the invention the protective element comprises heating means. The protective element can be heated by these heating means. Heating the protective element additionally effectively reduces the possibility of water shock. The heating means may, for example, comprise a simple heating wire which is formed in the interior of the protective element. According to a further aspect of the inventive idea, a measuring probe is proposed for use in the exhaust system of an internal combustion engine, in particular a lambda probe, a temperature sensor and/or gas concentration sensor which comprises at least one protective element according to the invention. According to one advantageous embodiment of the measuring probe according to the invention, the measuring probe comprises a measuring sensor, wherein the protective element comprises at least an inner surface which abuts at least partially against an outer surface of the measuring probe and/or of the measuring sensor and/or is formed at least partially opposite an outer surface of the measuring probe and/or of the measuring sensor. It is particularly preferred here for WO 2006/048192 - 10 - PCT/EP2005/011561 a gap to be formed between the outer surface of the measuring probe and/or of the measuring sensor and the inner surface of the protective element, at least in certain areas. The protective element can preferably be integrally formed on the measuring probe and/or the measuring sensor and/or be connected thereto in a materially joined fashion, in particular welded thereto. A positively locking and/or frictionally locking connection is also possible and in accordance with the invention. According to a further advantageous embodiment of the measuring probe according to the invention, said measuring probe comprises a protective cap, the protective element being formed between the protective cap and measuring sensor. A protective cap is generally formed in particular on lambda probes. In this case, the protective cap surrounds the measuring sensor, with suitable openings permitting the gas to be analyzed to pass to the measuring senor of the lambda probe which lies inside the protective cap. This protective cap serves primarily to avoid transportation damage and installation damage. Although such a protective cap is also intended to prevent water shock, that is to say for example a thermal shock to the generally heated measuring sensor through contact with water droplets, damage due to water shock occurs relatively often despite such protective caps, in particular if a motor vehicle is predominantly driven over short distances, that is to say generally in cold start phases. In such a case, the formation of the protective element according to the invention additionally between the protective cap and actual measuring sensor can further WO 2006/048192 - 11 - PCT/EP2005/011561 significantly reduce the risk of water shock, in particular in the case of lambda probes. According to a further aspect of the inventive idea, a honeycomb element, in particular a catalytic converter carrier element and/or filter element, is proposed which has cavities through which a fluid can flow, comprising at least one protective element according to the invention and/or at least one measuring probe according to the invention. The honeycomb element according to the invention may be constructed from metallic and/or ceramic materials, and in particular can be wound or layered and twisted or else extruded from at least partially textured metallic and/or ceramic layers and, if appropriate essentially smooth metallic and/or ceramic layers. According to a further advantageous embodiment of the honeycomb element according to the invention, the water-binding layer comprises at least partially a surface of the protective element which can be placed in fluid mechanical contact with the cavities. In fluid mechanical contact means in this context in particular that when a fluid, in particular exhaust gas, flows through the honeycomb element it can come into contact with or flow around the measuring sensor and/or protective element. In this case, the protective element effectively prevents water shock, in particular if it is formed at the location on the measuring probe with the greatest thermal capacity such as, for example, at a base at the junction between the measuring probe and outer casing pipe of the honeycomb element. According to a further aspect of the inventive idea, a motor vehicle, in particular an automobile, a motorized WO 2006/048192 - 12 - PCT/EP2005/011561 two-wheeled vehicle, an aircraft or a boat is proposed which comprises at least one honeycomb element according to the invention, one measuring probe according to the invention and/or one protective element according to the invention. The details and advantages which are disclosed for the protective element according to the invention can be transferred and applied in the same way to the measuring probe according to the invention, the honeycomb element according to the invention and/or the motor vehicle according to the invention. Further advantages and exemplary embodiments of the invention are explained with reference to the drawing without restricting the invention thereto. In said drawing: figure 1 is a schematic view of a honeycomb element according to the invention in cross section with a first exemplary embodiment of the protective element according to the invention; figure 2 is a schematic view of a second exemplary embodiment of the protective element according to the invention in cross section; figure 3 is a schematic, perspective view of a measuring probe according to the invention, and figure 4 is a schematic view of a measuring probe according to the invention in cross section. Figure 1 shows a honeycomb element 1 comprising a honeycomb structure 2 and an outer casing pipe 3. The honeycomb structure 2 is constructed in the present example by stacking and twisting essentially smooth layers 4 and at least partially textured layers 5 WO 2006/048192 - 13 - PCT/EP2005/011561 which, for the sake of clarity, are only shown partially. The layers 4, 5 can be constructed from metallic and/or ceramic material, in particular also filter material. The layers 4, 5 form cavities 6 through which a fluid can flow, in the present example ducts which extend from one end of the honeycomb elements 1 to the other. The outer casing pipe 3 comprises a measuring probe bore 7 in which a measuring probe 8 is placed. In order to secure the measuring probe 8 in the measuring probe bore 7, a connecting means 9, for example a thread, is formed which corresponds to matching connecting means (not shown) of the measuring probe 8. A protective element 10 is formed between the measuring probe bore 7 and the measuring probe 8. Said protective element 10 has a water-binding layer 11 which is formed on the surface of the protective element. 10 in such a way that when the exhaust gas flows through the honeycomb element 1 the protective element 10 comes into contact with the exhaust gas. In this context, the water-binding layer 11 is formed on the outside in relation to the measuring probe 8, i.e. in particular not on the inner surface 13 of the protective element 10 which is in direct contact with the outer surface 14 of the measuring probe 8. A carrier layer 12 is formed under the water-binding layer 11 and may be, for example, elastic or compressible. However, it is also possible and in accordance with the invention to form the entire protective element 10 as water-binding layer 11. Forming the water-binding layer 11, which as stated above permits the temporary chemical and/or physical binding of water, can effectively prevent water shock owing to water from water vapor contained in the exhaust gas, in particular in the cold start phase of the engine, condensing out before the honeycomb element 1 has therefore reached a temperature which is above WO 2006/048192 - 14 - PCT/EP2005/011561 the boiling point of water. In this context, the water- binding layer 11 acts as a type of sponge which temporarily stores water and releases it again. In the case of a water-binding layer 11 which binds water through absorption, the water can be released through desorption after a desorption temperature has been exceeded if the honeycomb element 1, and thus also the protective element 10 and water-binding layer 11, become hotter due to the heating through exhaust gas and the exothermal reaction which occurs. Figure 2 shows a measuring probe 8 with a second exemplary embodiment of a protective element 10 according to the invention in cross section. The protective element 10 is embodied here as a protective ring which completely surrounds the circumference of the measuring probe 8. An inner surface 13 of the protective element 10 abuts in an essentially gas-tight fashion against an outer surface 14 of the measuring probe 8. When there is essentially gas-tight abutment of the outer surface 15 of the protective element against an inner surface (not shown) of a measuring probe bore 7, the protective element 10 at the same time carries out a sealing function in order to effectively prevent exhaust gas emerging from the honeycomb element 1. Furthermore, heating means 16 are provided which in the present exemplary embodiment are composed of a heating coil. Other heating means 16 are possible and in accordance with the invention. Figure 3 is a schematic view of a measuring probe 8 according to the invention which has a thread 17 which corresponds to a connecting means 9 of a measuring probe bore 8, The actual recording of measured values is carried out here by means of a measuring sensor 18 which is embodied, for example, with rectangular- geometry as a semiconductor component. The measuring sensor 18 is surrounded by a protective cap 19 which WO 2006/048192 - 15 - PCT/EP2005/011561 protects the measuring sensor 18 against mechanical effects, for example. A protective element 10 according to the invention is formed in the interior of the protective cap 19 so that a gap 20 is formed between an inner surface 13 of the protective element 10 and an outer surface of the measuring sensor 18. This is advantageous in particular if the measuring probe 8 is designed so as to be heated, in particular in the region of the measuring sensor 18. In such a measuring sensor 18, the protective element 10 serves as an additional protection against possible water shock. Figure 4 is a schematic, cross-sectional view of a measuring probe 8 according to the invention, comprising a measuring sensor 18, a protective cap 19 and a protective element 10 according to the invention. The protective element 10 is embodied in such a way that an inner surface 13 of the protective element 10 is separated from an outer surface of a measuring sensor 18 by a gap 20, in which case the shape and size of the gap 20 can vary depending on the exemplary embodiment. The protective element 10 according to the invention effectively prevents water shock on the measuring probe 8 due to the formation of the water-binding layer 11 since water condensing out from water vapor in particular in the cold start phase at the point on the measuring probe 8 with the greatest thermal capacity is prevented.. The water-binding layer 11 temporarily binds the water in one operating state in order to release it again in another operating state. WO 2006/048192 - 16 - PCT/EP2005/011561 List of reference numerals 1 honeycomb element 2 honeycomb structure 3 outer casing pipe 4 essentially smooth layer 5 at least partially textured layer 6 cavity 7 measuring probe bore 8 measuring probe 9 connecting means 10 protective element 11 water-binding layer 12 carrier layer 13 inner surface of the protective element 14 outer surface of the measuring probe 15 outer surface of the protective element 16 heating means 17 thread 18 measuring sensor 19 protective cap 20 gap WO 2006/048192 - 17 - PCT/EP2005/011561 Patent claims 1. A protective element (10) for a measuring probe (8) , in particular a measuring probe (8) for use in the exhaust system of a motor vehicle, characterized in that the protective element (10) comprises at least one temporarily water-binding layer (11) which in a first operating state binds water chemically and/or physically and in a second operating state releases the bound water. 2. The protective element (10) as claimed in claim 1, characterized in that the protective element (10) has an essentially closed shape with an inner surface (13) and an outer surface (15), and is in particular in the form a ring and/or circular ring. 3. The protective element (10) as claimed in claim 1 or 2, characterized in that the protective element (10) is at least partially compressible or elastic. 4. The protective element (10) as claimed in one of the preceding claims, characterized in that at least the temporarily water-binding layer (11) is porous, and has in particular a porosity of at least 40%, preferably more than 70%. 5.. The protective element (10) as claimed in one of the preceding claims, characterized in that the protective element (10), in particular the water- binding layer (11), comprises at least one of the following materials: a) mica; b) aluminum oxide, in particular D-aluminum oxide; or c) zeolite, in particular zeolite A, X and/or Y and/or faujasite. WO 2006/048192 - 18 - PCT/EP2005/011561 6. The protective element (10) as claimed in one of the preceding claims, characterized in that said element (10) is temperature-resistant at temperatures up to 500°C, preferably 750°C, particularly preferably 1000°C. 7. The protective element (10) as claimed in one of the preceding claims, characterized in that the first operating state and the second operating state differ- in operating temperature. 8. The protective element (10) as claimed in claim 7, characterized in that the first operating state is present essentially at temperatures below a limiting temperature, in particular a desorption temperature, and the second operating state is present essentially at temperatures above the limiting temperature. 9. The protective element (10) as claimed in claim 8, characterized in that the limiting temperature is higher than the boiling temperature of water. 10. The protective element (10) as claimed in one of the preceding claims, characterized in that the water- binding layer (11) is located at least partially on a surface of the protective element (10) . 11. The protective element (10) as claimed in claim 10, characterized in that the water-binding layer (11) is formed at least partially on a surface of the protective element (10) which is at least partially on the outside in relation to the measuring probe (8) and/or in relation to a measuring sensor (18) . 12.. The protective element (10) as claimed in one of the preceding claims, characterized in that the protective element (10) is suitable for essentially gas-tight abutment against the outer surface (14) of WO 2006/048192 - 19 - PCT/EP2005/011561 the measuring probe (8) and/or of the measuring sensor (18). 13. The protective element (10) as claimed in one of the preceding claims, characterized in that the protective element (10) is suitable for essentially gas-tight abutment against an inner surface of a measuring probe bore (7). 14. The protective element (10) as claimed in one of the preceding claims, characterized in that the protective element (10) comprises heating means (16) . 15., A measuring probe (8) for use in the exhaust system of an internal combustion engine, in particular lambda probe, temperature sensor and/or gas concentration sensor, comprising at least a protective element (10) as claimed in one of claims 1 to 14. 16. The measuring probe (8) as claimed in claim 15, comprising a measuring sensor (18) , characterized in that the protective element (10) comprises at least an inner surface (13) which abuts at least partially against an outer surface (14) of the measuring probe (8) and/oz of the measuring sensor (18) and/or is formed at least partially opposite an outer surface (14) of the measuring probe (8) and/or of the measuring sensor (18). 17. The measuring probe (8) as claimed in claim 15, characterized in that a gap (20) is formed between the outer surface (14) of the measuring probe (8) and/or of the measuring sensor (18) and the inner surface (13) of the protective element (10), at least in certain areas. 18. The measuring probe (8) as claimed in one of claims 15 to 17, characterized in that the protective element (10) is integrally formed on the measuring WO 2006/048192 - 20 - PCT/EP2005/011561 probe (8) and/or the measuring sensor (18) and/or is connected thereto in a materially joined fashion. 19. The measuring probe (8) as claimed in one of claims 15 to 18, characterized in that the protective element (10) is connected in a frictionally and/or positively locking fashion to the measuring probe (8) and/or to the measuring sensor (18). 20. The measuring probe (8) as claimed in one of claims 15 to 19, which comprises a protective cap (19), characterized in that the protective element (10) is formed between the protective cap (19) and the measuring sensor (18). 21. A honeycomb element (1), in particular catalytic converter carrier element and/or filter element which has cavities (6) through which a fluid can flow, comprising at least one protective element (10) as claimed in one of the claims 1 to 14 and/or at least one measuring probe (8) as claimed in one of claims 15 to 20. 22. The honeycomb element (1) as claimed in claim 21, characterized in that the water-binding layer (11) comprises at least partially a surface of the protective element (10) which can be placed in fluid mechanical contact with the cavities (8). 23. A motor vehicle, in particular an automobile, a motorcycle, an aircraft or a boat, comprising at least one honeycomb element as claimed in claim 21 or 22, a measuring probe as claimed in one of claims 15 to 20 and/or a protective element as claimed in one of claims 1 to 14. The invention relates to a protective element (10) for attachment to a probe (8), especially a probe (8) for use in the exhaust gas system of a motor vehicle, whereby an inner surface (13) of the protective element (10) can at least partially be placed against an outer surface (14) of the probe (8). The protective element (10) comprises an at least temporarily water-binding layer (11) which chemically and/or physically binds water in a first operating state and releases the bound water in a second operating state. The configuration of the water-binding layer (11) of the protective element (10) according to the invention effectively prevents water shock on the probe (8) as water vapor is prevented from condensing out, especially in the cold start phase in the area of the probe (8) having the highest thermal capacity. The water-binding layer (11) temporarily binds the water in one operating state while it releases the water in a second operating state.

Documents:

01618-kolnp-2007-abstract.pdf

01618-kolnp-2007-claims.pdf

01618-kolnp-2007-correspondence others.pdf

01618-kolnp-2007-description complete.pdf

01618-kolnp-2007-drawings.pdf

01618-kolnp-2007-form 1.pdf

01618-kolnp-2007-form 2.pdf

01618-kolnp-2007-form 3.pdf

01618-kolnp-2007-form 5.pdf

01618-kolnp-2007-gpa.pdf

01618-kolnp-2007-international publication.pdf

01618-kolnp-2007-international search report.pdf

01618-kolnp-2007-other pct form.pdf

01618-kolnp-2007-pct request form.pdf

1618-KOLNP-2007-(01-12-2014)-ABSTRACT.pdf

1618-KOLNP-2007-(01-12-2014)-CLAIMS.pdf

1618-KOLNP-2007-(01-12-2014)-CORRESPONDENCE.pdf

1618-KOLNP-2007-(01-12-2014)-DESCRIPTION(COMPLETE).pdf

1618-KOLNP-2007-(01-12-2014)-DRAWINGS.pdf

1618-KOLNP-2007-(01-12-2014)-FORM-1.pdf

1618-KOLNP-2007-(01-12-2014)-FORM-2.pdf

1618-KOLNP-2007-(13-01-2012)-ABSTRACT.pdf

1618-KOLNP-2007-(13-01-2012)-AMANDED CLAIMS.pdf

1618-KOLNP-2007-(13-01-2012)-AMANDED PAGES OF SPECIFICATION.pdf

1618-KOLNP-2007-(13-01-2012)-DESCRIPTION (COMPLETE).pdf

1618-KOLNP-2007-(13-01-2012)-DRAWINGS.pdf

1618-KOLNP-2007-(13-01-2012)-EXAMINATION REPORT REPLY RECIEVED.PDF

1618-KOLNP-2007-(13-01-2012)-FORM 1.pdf

1618-KOLNP-2007-(13-01-2012)-FORM 2.pdf

1618-KOLNP-2007-(13-01-2012)-FORM 3.pdf

1618-KOLNP-2007-(13-01-2012)-FORM 5.pdf

1618-KOLNP-2007-(13-01-2012)-OTHERS.pdf

1618-KOLNP-2007-(13-01-2012)-PETITION UNDER RULE 137.pdf

1618-KOLNP-2007-(18-09-2012)-CORRESPONDENCE.pdf

1618-KOLNP-2007-CORRESPONDENCE.pdf

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