Urea-SCR Catalyst System Selection for Fuel and PM Optimized Engines and a Demonstration of a Novel Urea Injection System

This paper discusses the choice of catalyst types to reduce the NOx emissions down to the Euro V level. A novel Urea injection system is also presented, which is based on a mass produced digital dosing pump that is combined with an electronic control unit specially developed for controlling the Urea-SCR process onboard vehicles. It is shown that it is possible to have a NOx conversion above 80% with ammonia slip below 10 ppm using 30 liters of 130 cpsi catalysts for a 12 diesel engine. By increasing the cell density to 300 cpsi it is possible to reduce the catalyst volume by 2/3 down to 20 liters for the same engine.