BASF will introduce its LNT+CS4F emissions control system for diesel engines at the International Vienna Motor Symposium, which opens today.
The new system combines the features of a Lean NOx Trap (LNT) and a multifunctional catalyzed soot filter (CS4F). It can remove particulate matter, as well as carbon monoxide, hydrocarbons and nitrogen oxides from diesel-engine exhaust, helping automakers meet strict new emissions regulations including Euro 6c, BASF says.
Euro 6 legislation will be implemented in 2014. This legislation requires a significant decrease of NOx emissions to less than 80 mg/km when evaluated under the New European Driving Cycle (NEDC).
With the implementation of Euro 6c in 2017, still tighter requirements will come into play. Real Driving Emission (RDE) requirements will be applied, and will be evaluated using PEMS (Portable Emission Measurement Systems). These new conditions will lead to new challenges for the aftertreatment systems, BASF says.
To meet NOx emission limits under these demanding conditions, LNT catalysts for Euro 6c must have fast NOx adsorption kinetics and high NOx adsorption capacity when compared with LNT technologies developed for Euro 6a applications, BASF says. A multifunctional catalyzed soot filter (CS4F) is also required to remove PM plus convert secondary emissions like ammonia (NH3), hydrogen sulfide (H2S), CO, and HC resulting from soot filter and LNT regeneration, and to remove additional NOx, increasing the NOx reduction activity of the overall system.
The company says compared to the LNT+CSF+UF-SCR (Under Floor – Selective Catalytic Reduction) catalyst system already in the market, the LNT+CS4F system eliminates one catalytic component, resulting in lower system weight, space and complexity. However, a filter with high porosity is required to incorporate all these functions, and the component must be carefully designed so that it also meets the particle number regulation. In addition, the exhaust backpressure should not increase when changing from the LNT+CSF+UF-SCR system to the two-component LNT+CS4F system.
