Umicore Ag & Co. Kg

Degussa - Huls Ag

Stephan Eckhoff

Thomas Kreuzer

Stefan Franoschek

Wilfried Mueller

Ruediger Hoyer

Frank Adam

Egbert Lox

Anke Schuler

Ina Grisstede

Joerg-Michael Richter

Martin Votsmeier

Michael Lennartz

Frank-Walter Schuetze

Franz Dornhaus

Alfons Baiker

Harald Klein

Michael Schiffer

Katja Adelmann

Ulrich Goebel

Michael Seyler

Thomas R Pauly

Dirk Van Genechten

Susanne Kunert

Benjamin Barth

Marek Maciejewski

Hans Van Den Tillaart

Jurgen Leyrer

Meike Wittrock

Sebastian Mueller

Jan-Dierk Grunwaldt

Hans Van Tillaart

Maria Cristina Casapu

Aflons Baiker

Christian Lammarck

Leen Van Tendeloo

Frank Welsch

Susanne Philipp

The invention relates to a particle filter, which comprises a wall flow filter and SCR-active material, wherein the wall flow filter comprises ducts which extend in parallel between the first and the second end of the wall flow filter and which are alternately closed in a gas-tight manner either at the first or the second end and which are separated by porous walls, the pores of which have inner surfaces, and the SCR-active material is located in the form of a coating on the inner surfaces of the pores of the porous walls, characterized in that the coating has a gradient, such that the side of the coating facing the exhaust gas has a higher selectivity in the SCR reaction than the side of the coating that faces the inner surfaces of the pores. The SCR-active material is preferably a small-pore zeolite, which has a maximum ring size of eight tetrahedral atoms and is exchanged with copper and/or iron.

Particle filter having SCR-active coating

The present invention relates to an SCR-active material, comprising a small-pore zeolite, aluminum oxide and copper, characterized in that it contains 5 to 25 wt-% of aluminum oxide in relation to the entire material and that the copper is present on the aluminum oxide in a first concentration and on the small-pore zeolite in a second concentration.

SCR-active material

The present invention relates to the use of different regeneration strategies for nitrogen oxide storage catalysts (NOx storage catalyst, LNT or NSC), depending on the exhaust gas temperatures, to reduce in the total exhaust gas the greenhouse gas NO (nitrous oxide) that is produced as a secondary emission during the regeneration of the storage catalyst. If the exhaust gas temperature is below 275&#xb0; C.-290&#xb0; C., regeneration takes place using a strategy with short pulses of around 2 seconds and &#x3bb; Lambda 0.95 rich.

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The invention relates to a method for reactivating a system composed of an oxidation catalytic converter () followed by a possibly catalytically coated particle filter (), and to a correspondingly adapted exhaust-gas purification system for lean-burn engines () with low pressure EGR (). The present invention relates in particular to the reactivation of such a system during overrun operation of the engine.

Method and device for reactivating exhaust-gas purification systems of diesel engines with low-pressure EGR

The invention relates to a method for regenerating nitrogen oxide storage catalytic converters and to a correspondingly adapted exhaust-gas purification system for lean-burn engines. In particular, the present invention relates to the regeneration of nitrogen oxide storage catalytic converters during special driving situations of the vehicle.

Method for regenerating NOx storage catalytic converters of diesel engines with low-pressure EGR

The present invention relates to a regulating strategy for a special catalytic converter for exhaust-gas aftertreatment. The catalytic converter concept is distinguished in that at least two nitrogen oxide storage catalytic converters are used in the exhaust section of a vehicle. The first, possibly close-coupled unit is followed by one or more nitrogen oxide storage catalytic converters, which are possibly situated in the underbody of the vehicle. The nitrogen oxide storage catalytic converters are then regenerated as a function of the exceedance of nitrogen oxide threshold vales downstream thereof.

Regulating strategy for a catalytic converter concept for exhaust-gas aftertreatment having a plurality of nitrogen oxide storage catalytic converters

The present invention relates to a method for exhaust gas after-treatment for essentially lean-burn internal combustion engines and also a corresponding advantageous exhaust gas after-treatment system. In particular, the present invention relates to reducing the proportion of the greenhouse gas N20 in the total exhaust gas from a corresponding internal combustion system using at least one NOx storage catalyst as exhaust gas purification element. The objective of the invention is to operate the N20 depletion catalyst located downstream of the NOx storage catalyst under lambda=&#x3c;1 conditions when the N20 formed by the NOx storage catalyst reaches the N20 depletion catalyst.

Method of depleting nitrous oxide in exhaust gas after-treatment for lean-burn engines

The present invention relates to an exhaust-gas aftertreatment system which comprises a preferably catalytically active particle filter (wall-flow filter) which is followed in turn by a throughflow monolith (flow-through monolith) which is preferably provided with a catalytically active function. Both components have the same storage functions for gaseous substances present in the exhaust gas of internal combustion engines. The system is suitable in particular for the simultaneous removal of particles and pollutants from the exhaust gas of both predominantly lean-operated internal combustion engines and also of internal combustion engines operated predominantly with a stoichiometric air/fuel mixture. Likewise described is a process for the production and the use of such a system for exhaust-gas aftertreatment.

Exhaust-gas aftertreatment system with catalytically active wall-flow filter with storage function upstream of catalytic converter with identical storage function

A nitrogen oxide storage catalyst is provided, which has two catalytically active coatings on a support body. The lower coating applied directly to the support body has a nitrogen oxide storage function and includes platinum as a catalytically active component applied to a homogeneous magnesium-aluminum mixed oxide in combination with a nitrogen oxide storage material, in which a nitrogen oxide storage component is likewise present and applied to a homogeneous magnesium-aluminum mixed oxide. The second layer is notable for three-way catalytic activity, and includes palladium applied to aluminum oxide and barium oxide or strontium oxide, but no platinum.

Nitrogen oxide storage catalytic converter for use in a motor vehicle in a close-coupled position

Nitrogen oxide storage catalysts are used to remove the nitrogen oxides present in the lean exhaust gas of lean-burn engines. As a result of the stress due to high temperatures in vehicle operation, they are subject to thermal aging processes which affect both the nitrogen oxide storage components and the noble metals present as catalytically active components. The present invention provides a process with which the catalytic activity of a nitrogen oxide storage catalyst which comprises, in addition to platinum as a catalytically active component, basic compounds of strontium and/or barium on a support material comprising cerium oxide, said catalytic activity being lost owing to the thermal aging process, can be at least partly restored. The two-stage process is based on the fact that strontium and/or barium compounds formed during the thermal aging with the support material, which also comprise platinum, are recycled to the catalytically active forms by controlled treatment with specific gas mixtures.

Dual-stage method for the reactivation of thermally aged nitrogen oxide storage catalysts

To adhere to legal exhaust-gas regulations, the exhaust gases of a lean-burn engine must be freed from soot particles and nitrogen oxides. It is proposed that the cylinders of the lean-burn engine be divided into two groups which discharge their exhaust gases into two associated exhaust lines which each comprise a soot filter and which are merged at an opening-in point into a common exhaust line. The common exhaust line comprises the catalytic converter for the removal of the nitrogen oxides. By regenerating the two soot filters at different times, the exhaust-gas temperature in the common exhaust line is limited to a mean temperature between the exhaust-gas temperature of normal operation and that of regeneration operation, and the catalytic converter for the removal of the nitrogen oxides is preserved.

Method for regenerating soot filters in the exhaust gas system of a lean mix engine, and exhaust gas system therefor

An oxidation catalyst for internal combustion engines which contains platinum on a finely divided support material and containing lead as a promoter. The catalytic activity of the oxidation catalyst can be increased greatly by promoting the catalyst with lead at a molar ratio of lead to platinum of 2:1. The light-off temperatures of the promoted catalyst are well below the corresponding temperatures for a conventional, lead-free catalyst.

Oxidation catalyst for internal combustion engines

A process is disclosed for lowering nitrogen oxide levels in combustion engine exhaust gas by a reduction catalyst and by controlling the exhaust gas temperature upstream from the catalyst to a constant value, at which the catalyst exhibits maximum conversion for nitrogen oxides. It is possible to maintain maximum conversion over a wide range of engine outlet temperatures of the exhaust gas.

Process for lowering nitrogen oxide levels in combustion engine exhaust

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Alzenau, Germany

Stephan Eckhoff