Abstract
Methods and systems for treating NOx-containing exhaust from an internal combustion engine. An exhaust aftertreatment system has at least a PM control device and a downstream selective reduction catalyst (SCR) device. By using a bypass line to divert engine-out exhaust around the PM control device, or by introducing NO or NO2 from a non-engine source, the NO/NOx ratio into the SCR device can be controlled to a desired ratio for improved SCR efficiency.
Patent Number
8,562,924
Date Of Issue
Inventors
Charles E. Roberts Jr.