The Euro 6 standards involved the implementation of specific pollution control system for NOx in addition to a particulate filter, either for diesel light or heavy vehicles. Today, selective catalytic reduction (SCR) of NOx by urea seems necessary. However, for efficiency and space reasons, there is a strong interest in integrating SCR function in the particulate filter.
Today, no SCR catalytic system combines both resistance to thermal aging and an easy integration with the particulate filter. The main objectives of the program UreeNOx were to work both on the improvement of SCR catalysts as on their integration into the porosity of a particulate filter. This enabled strict control of emissions of NOx and particulates, insisting also on reducing CO2 emissions.
Expectations in terms of scientific and technical impacts are important for companies engaged in the project (PSA Peugeot Citroën, Volvo powertrain, Rhodia and CTI), with a short-term objective to provide a system of pollution control exhaust compatible with the standards, reduced congestion and socially competitive in terms of costs.
The project studied a specific pollution control system for NOx: the selective catalytic reduction (SCR) of NOx by urea and its integration into the particulate filter.
It has generated scientific and technical advances, some of which will have to be consolidated in future projects: new materials, integration of compact pollution control systems in particulate filters, reaction mechanisms involving urea, etc.