Efficient DeNox strategy for lean combustion engines

RWTH Aachen University starts research project on new exhaust aftertreatment systems for ultra-clean engines sponsored by Federal Ministry of Education and Research (BMBF)

In September 2017, RWTH Aachen University together with further partners started a joint research project on new exhaust aftertreatment systems for ultra-clean engines with highest efficiency. The project “Efficient DeNox strategy for lean combustion engines” is sponsored by the Federal Ministry of Education and Research (BMBF).

The project consortium consists of the RWTH facilities Chair of Thermodynamics of Mobile Energy Conversion Systems (TME), Institute of Inorganic Chemistry (IAC), Institute of Technical and Macromolecular Chemistry (ITMC) and the Central Facility for Electron Microscopy, the Institute for Materials Synthesis and Processing (IEK-1) at the Institute of Energy and Climate Research of Forschungszentrum Jülich GmbH as well as the companies Clariant AG, FEV Europe GmbH, Ford-Werke GmbH, DEUTZ AG, Sasol Germany GmbH and Umicore AG & Co. KG.

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The project offers the possibility to represent catalysts in its entirety for the first time: from material research to the production of materials and catalysts as well as the simulation and development of operation functions to the integration of the catalysts into the vehicle. Besides passenger cars, commercial vehicles and machines with combustion engines are included.

Recent and future emission legislations for combustion engines set very high requirements on engine management and the exhaust gas aftertreatment system, not only by strict emission limits and ambitious test cycles, but also by the rising efficiency goals. An important measure for the efficiency increase of modern engines resulting in a decrease of the specific CO2 emission per kilometer is the unrestricted (lean) operation with excess air. This requires a significant additional effort to clean the exhaust gas from emissions which are limited by law.

Until now two processes are technically realized. The storage catalyst works intermittent, it stores nitrogen oxide (NOx) in the catalyst and needs to be regenerated regularly during operation with excess fuel which can be achieved by a change of the engine operation. The SCR catalyst works continually with the help of additional AdBlue® which provides ammonia (NH3) as reductand. Future emission limits are only achievable through conceptual and technical modifications in the exhaust gas aftertreatment. For this purpose the known catalyst technologies – the storage catalyst and the SCR catalyst – shall be combined with the help of new materials resulting in a novel catalyst technology.

“The currently used catalyst technologies for NOx exhaust gas aftertreatment need to be developed further to fulfill future, even stricter emission limits. The goal of the project consortium therefore is the development of a novel catalyst joining both processes. We expect profound synergy effects which can be used to further improve the exhaust gas aftertreatment for lean combustion engines“, Professor Pischinger, Director of the Institute for Combustion Engines at RWTH Aachen University and spokesman of the project consortium states.

The project consortium moreover researches the optimization of the used materials based on models, the adaption of material production at suppliers, the improvement of coating for catalyst carriers, and the development of control-unit functions for the operation directly out of models. Moreover, the newly developed catalyst system will be tested on engine test benches before its implementation into the vehicle.

“The project partners contribute profound knowledge from different areas. This until now unique interdisciplinary cooperation enables a novel approach to a significant improvement of catalyst technology for lean combustion engines”, says Peter Dittmann, Chief Engineer at the Institute for Combustion Engines.