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Reduction of NOx in Lean-Exhaust by Selective-NOx-Recirculation


Objectives and content

Reduction of fuel consumption is one of the main objectives of the European car manufacturers in order to satisfy the request of the customers and to favour environmental protection. This objective is connected with the development of leanburn gasoline engines and an increase of the Diesel car market. However, with the stringent emission regulations of the near future, both in Europe and in the United States, it is necessary to develop new technologies enabling improved emission reduction capability, using exhaust after treatment systems for these types of engine. Whereas the three-way-catalyst is a well established technology for efficient reduction of NOx emission from gasoline engines operating under stoichiometric conditions, there is no appropriate technique available for the Diesel or leanbum gasoline engine. Despite of world-wide research efforts using the most promising SCR technique it is not available for use in production vehicles.
The objective of this project is to assess the potential for reducing NOx emission from lean-exhaust using a new 'Selective NOx-Recirculation' technique. Particular compounds like perovskites are able to adsorb large amounts of NOx and thus can be used in a first step for a selective extraction of NOx from the exhaust and temporary storage. In a second step the stored NOx is desorbed and fed back into the intake air. Thus the NOx is recirculated selectively back into the combustion chamber of the engine and decomposed by the combustion process itself. The first aspect of the project will be devoted to the development of NOx adsorbents able to store large quantities of NOx under lean conditions (synthesis of powders, surface characterisation and reaction dynamics, development of coating methods). The second aspect will consist of the study of NOx decomposition by the combustion process (experimental and numerical). Results of both project parts will be applied in a demonstrator equipped with an IDI or Dl Diesel engine in order to validate the performance of the SNR system.

The industrial members of the project are composed of one European car manufacturer (Daimler-Benz) and one European catalyst supplier (Emissionsteknik). Three universities with high competence in the development of new materials (University of Leuven, University of Strasbourg) and in material characterisation and reaction dynamics (University of Goteborg) will complement the project. All together the project partners will represent four different countries with five areas of expertise.

Funding Scheme

CSC - Cost-sharing contracts


Daimler-Benz AG
70567 Stuttgart

Participants (4)

3,Fysikgränd 3
412 96 Goeteborg
92,Kardinaal Mercierlaan 92
3001 Heverlee
Svenska Emissionsteknik AB
8,Victor Hasselblads Gata
421 31 Gothenburg
École Européenne des Hautes Etudes des Industries Chimiques de Strasbourg
1 Rue Blaise Pascal
67008 Strasbourg