Abstract
Keywords: Diesel emission reduction, diesel particle filter, SCR, limited & unlimited emissions, deNOx
New Diesel exhaust gas aftertreatment systems, with DPF*) and deNOx (mostly SCR) inline application are very important step towards zero emission Diesel fleet. Solid quality standards of those quite complex systems are urgently necessary to enable decisions by several authorities.
The Swiss Federal Office of the Environment BAFU and the Swiss Federal Roads Office ASTRA decided to support further activities of VERT to develop appropriate testing procedures and to define the quality criteria.
The present report informs about the international network project VERT *) dePN (deactivation, de-contamination, disposal of particles & NOx), which was started in Nov. 2006 with the objective to introduce the SCR-, or (DPF+SCR)-systems in the VERT verification procedure. Examples of results with some investigated systems are given. The most important statements are:
- the investigated combined aftertreatment systems (DPF+SCR) for dynamic engine application efficiently reduce the target emissions with deNOx-efficiency up to 92% (if operated in the right temperature window) and filtration efficiency based on particle count up to 100%,
- the average NOx conversion rate at transient operation (ETC) depends strongly on the exhaust gas temperature profile and the resulting urea dosing control,
- the NP filtration efficiency, which is verified at stationary engine operation is perfectly valid also at the transient operation.
The present results will be confirmed in the further project activities with other systems and with different testing cycles. A special attention will be paid to the operational profiles, which are representative for low emissions zones LEZ.