DeNOx removal techniques for automotive applications – A review

Abstract

A sector that contributes immensely to global warming due to the release of harmful gases into the atmosphere annually is the automotive industry. This has led to several optimization of diesel engines from their initial inert system with lower power density to fast running types with higher power densities. Despite these modifications coupled with the introduction of Diesel Oxidation Catalyst (DOC) and Diesel Particulate Filter (DPF), there are still environmental concerns that need to be critically analyzed. The current types of diesel engines have challenges pertaining to NOx reduction due to their lean operations. These limitations further led to the technological evolution of Selective Catalytic Reduction and NOx storage catalysts (NSC). This investigation therefore explored the current state of Selective Catalytic Reduction (SCR) and NOx storage catalyst (NSC). The effect of temperature and uniform distribution of ammonia associated to these technologies were critically reviewed. Factors impeding the integration of these technologies in the automotive industry were also discussed Possible solutions to mitigate these challenges were proposed. From the review gathered, there is still the need for further research activities in this field in terms of optimization to enhance the overall performance of diesel engine cars with lower toxic emission.