SCR and SCRi ^® as After-treatment Systems for Low CO ₂ and Low NOx Vehicles

On one hand, latest worldwide emissions legislation developments aim to reduce NOx and Particulate Matter (PM) emissions of all diesel engines, while on the other hand lower fuel consumption diesel engines are still required for lower fleet average CO₂ emissions. As a consequence of the chosen CO₂ optimized combustion mode, the raw NOx emission increases and as such Selective Catalytic Reduction (SCR) technology will be the future choice for high efficiency NOx aftertreatment. This paper deals with SCR technology and its derivative SCRi® technology, when diesel particle reduction is required, especially for heavy-duty applications. Alongside the developed metal catalyst technologies, a complete SCR reducing agent dosing system is presented. Emission results gained with the SCR or SCRi® technologies on European commercial engines illustrate the potential of these technologies for conversion of NOx and PM emissions. This enables drafting of a road map for future emission control solutions, considering the local situation in India, for upcoming legislations.