DE102004034269A1 - Producing a channeled substrate for a catalytic converter or particulate filter for a motor vehicle engine comprises building up the substrate by screen printing - Google Patents

Abstract

Producing a substrate for a catalytic converter or particulate filter for a motor vehicle engine, where the substrate has channels running throught it in the direction of exhaust gas flow, comprises building up the substrate by screen printing. Independent claims are also included for: (1) a substrate produced as above in which the cross-sectional shape of a channel varies as a function of position in the direction of flow; (2) catalytic converter or particulate filter comprising a substrate as above in a housing.

Description

The The invention relates to a method for producing a substrate for one Catalyst and / or a particulate filter according to the preamble of the claim 1, a substrate produced by such a method according to the preamble of claim 9, as well as having such a substrate Catalyst and / or particle filter according to the preamble of the claim 12th

catalysts and / or particulate filters are used for emission control, especially for lean Operable Otto internal combustion engines and diesel internal combustion engines needed and used. Such catalysts have a substrate which, with a suitable catalytic coating for conversion, Storage and cleaning provided the existing exhaust gas components is. Such a substrate, which is also called a monolith, is in the flow direction of the exhaust gas traversed by a plurality of channels. In the case of a particulate filter are the walls of the channels porous and the channels are mutually closed so that the exhaust gas is forced the porous ones To cross walls whereby the filter effect with respect to the exhaust particles caused becomes. Furthermore, in the case of the particulate filter are also catalytic Depending on the application, coatings are arranged on and / or in the channel walls.

such, of channels crossed substrates for Catalysts and particle filters are predominantly produced by extrusion extrusion prepared, as described for example in DE-A-4215481 is. A catalytically active ceramic composition becomes a with honeycomb channels Extruded with predetermined wall thickness substrate extruded. adversely it is that the cross-sectional shape of the honeycomb channels over the length in the preparation by means of an extrusion process can not be changed. Due to this uniform honeycomb shape of the channels turns on the flow the substrate with the exhaust gas to be cleaned very quickly a laminar Flow, which the conversion of the exhaust gas to the on the walls of the Substrate applied Washcoat impeded.

Of the The invention is therefore based on the object, a process for the preparation one with channels solid substrate for use in a catalyst and / or to provide a particulate filter, wherein the cross-sectional shape of the Channels changeable is. Further, the invention has the object, a traversed with channels Substrate of the generic type to provide variable cross-sectional shape.

The The object is achieved by a method having the features of the claim 1 and solved by a substrate having the features of claim 9. preferred embodiments The invention are the subject of the dependent claims.

at the method according to the invention for producing a substrate for a catalyst or a Particulate filter of an internal combustion engine of a motor vehicle, the in the flow direction the exhaust gas with channels is traversed, the substrate by means of a screen printing process built up.

Especially is the substrate by successively performing a plurality n, n> 1, of screen printing steps constructed, each Siebdruckschritt a screen printing layer of the Substarts forms.

Preferably become a variable screenprint mask and / or different screen printing masks for creating the respective Screen printing layer used.

• a) Anordnen einer Siebdruckmaske auf oder über einem durch die (i-1)-Siebdruckschritten gebildeten Substratblock,
• b) Füllen der Siebdruckmaske mit dem Substratmaterial, und
• c) Andrücken der gefüllten Siebdruckmaske auf dem Substratblock, wodurch die i-te Substratschicht auf dem Substratblock aufgetragen wird

In particular, the i-th screen printing step, i = 1... N, of the plurality n of the screen printing steps consists of the following steps:

• a) arranging a screen-printing mask on or above a substrate block formed by the (i-1) screen printing steps,
• b) filling the screen mask with the substrate material, and
• c) pressing the filled screen mask on the substrate block, whereby the i-th substrate layer is applied to the substrate block

Preferably is the by the inventive method generated substrate block on a height-adjustable platform arranged after pressing the i-th layer, i = 1 ... n, moves down by one layer thickness becomes.

As already mentioned above, a variety of different screen masks is preferably used, which can be arranged in particular on a roll.

Preferably is used as a substrate material for the screen printing suitable ceramic material and / or composite fibers used.

An inventive substrate, also referred to as a monolith, for a catalyst or a particulate filter of an internal combustion engine of a motor vehicle, which is produced by the method described above, is durchzo in the flow direction of the exhaust gas with channels gene, wherein the cross-sectional shape of a channel is a function of the location in the substrate flow direction.

there is preferably the change the cross-sectional shape of a channel as a function of location in the direction of flow the exhaust gas suitably to increase flow turbulence designed the exhaust gas, for example, in which the channels a or more flaps or protrusions by which the turbulence in the channel is increased, so that a laminar flow is avoided.

One Inventive catalyst and / or Particulate filter with a substrate described above has a housing, in which the substrate is arranged.

A preferred embodiment de invention will be explained below with reference to the drawing.

1 shows a schematic representation of the method according to the invention.

1 Fig. 3 depicts the method according to the invention, wherein the i-th step, i = 1, ... n, is shown, and shows a substrate 1 , also as substrate block 1 referred to on a height-adjustable platform 2 is arranged. The illustrated substrate block 1 was formed by the previous steps i-1 of the method. Above the substrate block 1 is a screenprint mask 3 arranged. The screenprint mask 3 is elastic and flat within a mask web 5 arranged so that a variety of different screen masks a role 6 form. The current, above the substrate block 1 arranged screen print mask 3 is now filled with the screen printing material that passes through the Materialandruckrolle 4 on the substrate block 1 is applied. After application of the i-th screen printing layer, the platform moves 2 down the thickness of the screen printing layer, so that the next screen printing layer i + 1 can be applied. This can be done using the current screenprint mask 3 done or the role 6 is by the Rollvorichtung 7 or rolling device 8th moved in or opposite to the direction of the arrow to the next screen mask (not shown) above the substrate block 1 to arrange and create the next screen printing layer.

1

substratum

2

platform

3

screen printing mask

4

pinch

5

mask train

6

role

7

rolling device

8th

rolling device

Claims (12)

Method for producing a substrate ( 1 ) for a catalytic converter or a particulate filter of an internal combustion engine of a motor vehicle, which is traversed by channels in the flow direction of the exhaust gas, characterized in that the substrate ( 1 ) is constructed by means of a screen printing process. Method according to claim 1, characterized in that the substrate ( 1 ) is constructed by successively performing a plurality n, n> 1 of screen printing steps, wherein each screen printing step of a screen printing layer of the substrate ( 1 ). Method according to claim 2, characterized in that that a changeable one Screen print mask and / or different screen print masks for creation the respective screen printing layer can be used. Method according to one of claims 2 or 3, characterized in that the ith screen printing step, i = 1 ... n, of the plurality n of screen printing steps consists of the following steps: a) arranging a screen printing mask ( 3 ) on or above a substrate block formed by the (i-1) screen printing steps ( 1 ), b) filling the screen mask ( 3 ) with the substrate material, and c) pressing the filled screen mask on the substrate block ( 1 ), whereby the i-th substrate layer on the substrate block ( 1 ) is applied Method according to claim 4, characterized in that the substrate block ( 1 ) on a height-adjustable platform ( 2 ) is arranged, which is moved after pressing the i-th layer down by one layer thickness. Method according to one of claims 4 or 5, characterized in that a plurality of different screen printing masks ( 3 ) is used. Method according to claim 6, characterized in that the screen printing masks ( 3 ) on a roll ( 6 ) are arranged. Method according to one of the preceding claims, characterized in that the sub stratmaterial is suitable for screen printing ceramic material and / or composite fibers. Substrate ( 1 ) for a catalytic converter or a particle filter of an internal combustion engine of a motor vehicle, which is traversed in the flow direction of the exhaust gas with channels, produced by a method according to any one of the preceding claims, characterized in that the cross-sectional shape of a channel is a function of the location in the substrate flow direction. Substrate according to Claim 9, characterized that change the cross-sectional shape of a channel as a function of location in the direction of flow the exhaust gas suitably to increase flow turbulence the exhaust gas is designed. Substrate according to Claim 10, characterized that the channels have one or more flaps. Catalyst and / or particle filter with a substrate ( 1 ) according to any one of claims 9 to 11 and a housing in which the substrate ( 1 ) is arranged.