The three existing DeNOx solutions
Progress towards "clean" cars is being strongly driven by increasingly strict international standards. For instance, the Euro 5 standard currently in effect within Europe requires nitrogen oxide emissions from Diesel and gasoline engines to be cut by 20% to 25%. This standard will be superceded by Euro 6 in 2014, which takes a much harder line toward NOx emissions and consequently implies the use of DeNOx systems.
Designing and producing DeNOx systems calls for three processes and three areas of expertise: Selective Catalyst Reduction (SCR), NOx traps and exhaust gas recirculation (EGR).
• Selective Catalyst Reduction (SCR) : a technology that strongly reduces nitrogen oxide emissions (NOx) from the exhaust by means of an additional SCR catalyst. With this technology, the vehicle needs to be fitted with an Adblue tank containing an aqueous solution with a 30% urea content.
• NOx trap : another technology that reduces nitrogen oxide emissions (NOx) from the exhaust. These traps look like normal catalytic converters, but contain precious metals (platinum / palladium / rhodium).
• "Low-Pressure Exhaust Gas Recirculation" (LP-EGR) : a low-pressure EGR loop that limits the production of NOx in the combustion chamber. The exhaust gases are recovered after the particulate filter by a back pressure valve and returned to the intake to lower the temperature.
Faurecia is capable of integrating these three types of technology to tackle any problems automakers face.