Johnson Matthey - Hydrocarbon-SCR Systems

Hydrocarbon-SCR (lean NOx reduction) systems use hydrocarbons as the reductant. The hydrocarbon may be that occurring in the exhaust gas (`native`) or it may be added to the exhaust gas. This has the advantage that no additional reductant source (e.g. urea) need be carried but these systems cannot offer the performance of ammonia-SCR systems.