Caterpillar Inc.
Aftertreatment system and method

Abstract:

An aftertreatment system for treating exhaust gases from an internal combustion engine includes, in series, a diesel oxidation catalyst (DOC), a diesel particular filter (DPF) downstream the DOC, and a primary selective catalyst reduction (SCR) catalyst downstream the DPF. A supplemental SCR catalyst is disposed upstream the DOC, DPF, and primary SCR catalyst to receive raw exhaust gases from the internal combustion engine. The supplemental SCR catalyst may conduct an SCR reaction on the raw exhaust gases until the supplemental SCR catalyst reaches a reaction temperature, at which time the supplemental SCR catalyst may conduct the SCR reaction.