The catalytically active structure

 

The invention relates to flow to the exhaust gas of the internal combustion engine catalytically active structure, especially to a cellular structure formed of at least one metal sheet having a catalytically active surface. Described catalytically active structure, which is formed of sheet metal with a catalytically active surface. The surface of the sheet metal at least partially provided with a catalytically active metal oxide layer, the metal oxide is an oxide of a metal of the fourth period, selected from the group including Ti, V, Zn, Fe, Cr, Mn, Ni, Cu, Co. Effect: reduction of toxic components in the exhaust gases of the internal combustion engine. 2 C.p. f-crystals, 5 Il.

The invention relates to a flow for the exhaust gases of the internal combustion engine (ice) catalytically active structure, especially to a cellular structure formed of at least one metal sheet having a catalytically active surface.

To reduce the content of toxic components such as unburned hydrocarbons, co pererasti. This structure can be formed of a monolithic ceramic honeycomb element. Also known structures formed rolled into a roll and/or accumulated in the packet of metal sheets. Metal structure covered with a thin layer of aluminum oxide. This aluminum oxide increases the surface area of the structure. On aluminiumoxide layer is divided catalytically active material. This material contains platinum, rhodium and palladium.

In order to ensure the most efficient operation of the catalytic Converter of the EXHAUST gas requires accurate control of the air-fuel mixture, which can be determined by the composition of the EXHAUST gas. To do this, in the exhaust manifold before, when viewed in the direction of flow of the EXHAUST gas catalytic Converter install the oxygen sensor (also called a lambda sensor). This lambda probe connected to the control system of internal combustion engines, which allows you to manage the process of mixture formation in internal combustion engines. Such systems designed to reduce the content in the emissions of toxic components, also called three-component catalytic converters EXHAUST gas for vehicles.

In article Nonnenmann, entitled "fur Abgaskatalysatoren in Kraftfah the practical catalysts, which are made of a catalytically active metal sheets, for example, Monel metal, but which are not widely used.

In areas that use internal combustion engines of small capacity, which are equipped, for example, lawn mowers, benzinmotor chain saws, single vehicle (with an engine displacement of up to 50 cm3and a maximum speed of up to 69 km/h), etc., also tend to reduce the content of toxic components in the EXHAUST gas such internal combustion engines using catalytically active structures. However, for such internal combustion engines are not permitted by the control system and the lambda probe in the exhaust manifold, and therefore mixing with the aim to minimize the formation of harmful substances in this case is impossible.

Internal combustion engines of small capacity are enriched combustible mixture, i.e., with excess fuel. Therefore, when the operation of such engine, the main problem is that in the catalytically active structure falls and burns a large amount of unburned hydrocarbons. In the result there is a danger of formation of the so-called "hot spots" that can lead to the destruction of the catalytically active surface. It should atashost vitrification (melting) of the coating, in the result, these catalytically active structures have only a limited service life.

Based on the foregoing, the present invention was used to develop the catalytically active structure, which could be used for internal combustion engines that do not have a management system carburetion.

This task is solved in accordance with the invention using patterns with distinctive features according to p. 1 of the claims. Preferred embodiments of the provided in the respective dependent claims.

Proposed in the invention structure, which preferably has a honeycomb structure formed of at least one metal sheet having at least one catalytically active surface. The surface of the sheet metal at least partially provided with a catalytically active metal oxide layer. The specific activity of the specified metal oxide layer with a lower specific activity of the catalytically active metals selected from the group of noble metals, such as used in a three-component catalytic converters. Such catalytically active structure of a CR is neobrazovannie, because excess fuel catalytic transformation on the surface of the metal oxide layer is subjected to only a part of it, making it possible to avoid the formation of so-called "hot spots".

The above metal oxide layer is made directly on the metal sheet that allows you to refuse the application serves as a substrate layer of aluminum oxide and to facilitate in the production of such patterns.

In one preferred embodiment of the structure according to the invention it is proposed to perform the metal-oxide layer on the base metal, which is a component of the sheet metal material. The advantage of this variant lies in the fact that the metal oxide layer is integrated into the sheet metal material and provides a result of the strong adhesion of the metal oxide layer with this metal sheet. To obtain such a metal oxide layer in the oxide film by heat treatment of sheet metal in an oxidizing atmosphere.

In another preferred embodiment, the structure is proposed to obtain the metal oxide layer by oxidizing deposited on a metal sheet metallicity rolling. In addition, a metal coating can be applied on the metal sheet by immersion of the base material in the liquid metal. In another embodiment, the metal coating can be applied to sheet metal coating. When forming a metal coating metal can be applied in liquid form or in the form of pulverulent material. Depending on what type of metal is used for the formation of the metallic coating, the latter may be obtained by electrolytic deposition.

The metal coating does not necessarily apply to the entire surface of the sheet metal. It can be applied on individual sections of sheet metal. The metal oxide layer is also obtained by oxidation of the metal coating deposited on a metal sheet.

The metal sheet can also be applied finish metal oxide layer, so that the metal sheet immediately after applying to a metal oxide layer has a catalytic activity.

In another preferred embodiment, the structure is proposed to obtain the metal oxide layer to use a metal with a higher oxidation potential in comparison with the components of the material metallitootajana, to the specified metal does not form a stable passivating film at the temperatures prevailing when using the catalytically active structure.

According to another variant execution patterns preferably, the metal oxide, respectively, of the oxide of the metal, had at most only a low ability to diffuse into the metal sheet. This prevents diffusion of the metal to form a metal oxide, respectively, the diffusion of the metal oxide inside the metal sheet, the metal sheet does not remain catalytically active metal oxide layer. Low diffusion capacity must be preserved above all and at elevated temperatures.

In order to avoid any, even very small, reducing the catalytic activity of the metal oxide layer, including as a result of diffusion of components of the sheet metal material in the metal oxide layer, the structure is proposed to perform such a way that any component of the sheet metal material had a low ability to diffuse into the metal oxide layer, respectively, in this met Gasunie metal oxide layer components of sheet metal material.

In the following a preferred embodiment of the structure according to the invention it is proposed to use as oxide metal oxide metal of the 4th period. First of all it is advisable to use the oxide of the transition metal. Preferably as a metal oxide to apply a metal oxide selected from the group including Ti, V, Zn, Fe, Cr, Mn, Ni, si, Co. The preferred metal oxide is titanium oxide having a relatively high catalytic activity compared with other oxides of this group of metals. Sheet metal, such as preferably from a material containing titanium as an alloying agent. In addition, the sheet metal material can contain as components of an alloy of iron, chromium and Nickel.

Preferably used as the metal oxide, the zinc oxide is formed on the corrosion-resistant material basis. The catalytic activity of zinc oxide during the oxidation reaction is relatively high, while it is higher than that of iron oxide or chromium. The zinc layer in the form of metal coatings can be obtained by immersing a metal sheet in a liquid zinc or coated with zinc (in liquid form or in the form of ima in the invention structure is described in more detail below on the example of some of the variants of its implementation with reference to the accompanying drawings, which is shown in Fig.1 is a schematic depiction of a structure 1 of Fig. 2 is a schematic depiction of sheet metal to the metal oxide layer of Fig. 3 is a first example is shown schematically an apparatus for manufacturing sheet metal to the metal oxide layer of Fig. 4 is a second example is shown schematically an apparatus for manufacturing sheet metal to the metal oxide layer, and Fig. 5 is a third example is shown schematically an apparatus for manufacturing sheet metal to the metal oxide layer.

In Fig.1 as an example, schematically shows the structure 1. This structure 1 has a generally honeycomb structure. It is formed by the corrugated layers 2 and smooth 3 metal sheets. Corrugated 2 and smooth 3 metal sheets typed in the package and S-shaped folded into a roll. Corrugated 2 and smooth 3 metal sheets restrict the flow channels 5 for the flow of the EXHAUST gas of the internal combustion engine. Corrugated 2 and smooth 3 metal sheets are located in the tubular casing 4.

Structure 1 shown as an example in Fig.1, has a catalytic effect. When the flow of the EXHAUST gas of the internal combustion engine schematically shows a metal sheet 2, represents a sheet of metal foil. This metal sheet 2 has a catalytically active surface 6. The catalytically active surface 6 of the metal sheet 2 is formed of the metal oxide layer 7. Such metal oxide layer 7 can be covered the entire surface of the sheet metal. In addition, the metal oxide layer 7 can have 2 corrugated and smooth 3 metal sheets. Metal oxide layer 7 is a layer of oxide formed in the oxidation of the base metal.

To obtain the metal oxide layer 7 on the metal sheet 2 in accordance with Fig.3 offers a continuously flowing sheet metal 2' with non-oxidized surface through the device 8 oxidation. This device 8 oxidation has a camera 12, in which the predominant atmosphere conducive to the formation of the metal oxide film. In addition, the device 8 oxidation is not shown in the drawing, the heater through which the camera 12 is set to the temperature required for the formation of metal oxide layer 7. The metal sheet 2' is preferably heated in the device 8 to oxidation up to a temperature of at least 350oC and kept at atlasnova depend on the material of the metal sheet 2' and the oxidative atmosphere in the chamber 12. When forming the metal oxide layer 7 individual parameters of the oxidation process can be adjusted so as to obtain on sheet metal 2 metal oxide layer 7 with the required properties.

Metal oxide layer 7 is obtained on the metal sheet 2 Fig.3 oxidation of the metal component of the metal material sheet 2'. The metal oxide layer preferably has a higher oxidation potential in comparison with the rest of the sheet metal material 2. Oxidation of the metal sheet 2' preferably so that this metal sheet 2' did not fully depleted metal, forming a metal oxide layer in the oxide film.

Metal alloy for sheet metal fabrication 2' should also find a similar composition to the metal oxide layer, respectively, the metal oxide at most only slightly was diffundiruet in sheet metal. This creates prerequisites for the actual formation of the metal oxide layer 7. To give a metal oxide layer 7 ultimate activity preferably also to other components of the material. the result of the oxidation process will take place faster than the diffusion component of the sheet material in the metal oxide layer, thereby preventing the formation of a mixed oxide. The metal oxide layer preferably is an oxide film formed by the oxides of metals, primarily TiO2V2O5, ZnO, Fe2About3, CR2About3, MnO2, NiO, CuO and/or Co3O4. More preferably, however, to perform a metal oxide layer made of titanium oxide.

The oxidation can be carried out not only continuous, but also in periodic mode, putting in the latter case, the oxidation of at least one metal sheet 2'. However, from the point of view of economic efficiency, it is sensible to use a continuous manufacturing process.

In Fig.4 schematically shows a second embodiment of a device for manufacturing sheet metal 2 metal oxide layer 7. This unit has a unit 9 for coating. Unit 9 on the metal sheet 2, which can be used a metal foil is applied to the metal 10. This metal 10 forms on the surface of the metal sheet 2' metallic coating 11. Then prepare is tiravanija is oxidation of the metal coating 11. Oxidized metallic layer 11 forms a metal oxide layer 7 according to the invention. In the chamber 12 is predominant oxidizing atmosphere. The device 8 oxidation is not further shown in the drawing heaters, which heat the metal sheet with a metallic coating 11. Along with the oxidation of the metallic coating 11 is also a compound of the metal, respectively, of metal oxide metal oxide layer 7, the metal sheet 2.

Apply metal 10 on the metal sheet 2' can be physical or chemical means. Depending on the technology of coating on the metal sheet 2' you can refuse additional oxidation in a separate device 8 oxidation when the metal 10 is applied on the metal sheet 2' in an oxidizing atmosphere. Apply a metal can, for example, by spraying molten metal in an oxidizing atmosphere.

Unit 9 for coating allows you to put the metal on certain parts of the metal sheet 2'. In addition, the metal sheet 2 can also be performed with the metal oxide layer 7, which may contain various metal oxides or have areas containing various metal oxides.

In Fig. 5 shows a diagram of asetkey metal sheet 2 with the metal oxide coating 7 made by carried out by rolling the cladding metal sheet 2' foil 13 of the metal oxide. If necessary, made so metal sheet 2 with the metal oxide layer 7 can be subjected to subsequent processing operations, in particular heat treatment, in which is formed a lasting connection metal layer 7 with the metal sheet 2.

As the metal sheet 2, respectively 2', it is preferable to use a metal foil of a thickness of about 8 μm. Such metal foil, in turn, represents, in particular, a titanium foil with a stabilizing additives of iron, chromium and vanadium. Such titanium foil has a very high plasticity that allows it to be used primarily for the manufacture of structured, i.e., profiled metal sheets.

There is also an alternative way to perform the sheet metal to the metal oxide layer by dip galvanizing and oxidation in an oxidizing atmosphere corrosion resistant, does not contain aluminum metal foil.

Claims

1. Flowing to the exhaust gas of the internal combustion engine catalytically active cell structure, which is formed by at least one Metallichesky active metal oxide layer, formed in the oxide film deposited on a metal sheet metallic coating, wherein the metal oxide is an oxide of a metal of the fourth period, selected from the group including Ti, V, Zn, Fe, Cr, Mn, Ni, Cu, FR.

2. Structure on p. 1, characterized in that the metal oxide layer has a higher oxidation potential in comparison with the components of the sheet metal material.

3. Structure under item 1 or 2, characterized by the presence of at least a slight diffusion of the metal of the metal oxide in the metal sheet.

 

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