Last years' experience with SCR dosing systems has gone from Air-assisted (AA) products to Airless (AL) technologies. The SCR algorithms have developed to rather sophisticated programs that can deal with accuracy, aging prediction and diagnostic agents and messages. All systems are still in use and have specific advantages and drawbacks.
This paper reflects over the past years of SCR development from Euro 4, Euro 5 and future Euro 6 platforms and over the different needs by customers dealing with systems in the above categories. This includes developments in material compatibility, systems development, application areas, algorithms and diagnostics. This is, of course, of particular interest for the future product needs but also for the region where the regulatory requests are getting stronger.
Also the paper deals with experience from systems design and highlights some of the possible pitfalls making it necessary to include knowledge/experience and component matching from the whole exhaust systems including not only the dosing system but also the nozzles, algorithms, topology, mixers and catalysts.
All experiences reported are in the area of heavy duty on and off high way applications.