Achieving ultra-low NOx emissions remains a major challenge in diesel emission control industry worldwide, especially as increasingly stringent regulations are introduced globally. Selective Catalytic Reduction (SCR), the leading NOx reduction technology in diesel systems, performs best when “sufficient” heat and ammonia are made available to it. At the same time, any proposed solution must be both low-cost and functionally robust in an industry seeking near 100% NOx removal at the lowest feasible cost.
This work presents a low-cost architecture, utilizing a small, highly compact, single heater-mixer unit along with a light-off (close-coupled) SCR for meeting most stringent NOx emission regulations worldwide. It also hinders deposit formation lowering warranty costs and mitigating failure modes. Engine studies using a fully-aged aftertreatment system demonstrate that the proposed solution enables compliance with newer heavy-duty regulations including 2027 US, Euro-VII, China-VII, and likely the upcoming Bharat-VII while also rendering a large ‘compliance margin’, providing significant margin for meeting in-use compliance.