Patent ID: 8857154
Filing Date: 2014-10-14
Classification: F01N,F02D,Y02T

Abstract:
1. A method of treating NOx-containing exhaust from an internal combustion engine, the engine having an exhaust manifold, the method comprising: providing an exhaust aftertreatment system having the following devices arranged in the following order downstream the exhaust manifold: a lean NOx trap (LNT), a particulate filter (PF) and a selective reduction catalyst (SCR) device; wherein at least the LNT is located in the engine compartment such that it is heated by the engine and is formulated to oxidize NO to NO2 as the engine warms up immediately after cold start without the aid of a reductant; monitoring the SCR temperature at the input to, or in, the SCR; comparing the SCR temperature to a predetermined threshold to determine whether the aftertreatment system is to be operated in a cold mode or warm mode; providing reductant to the SCR only in warm mode; accumulating NOx in the LNT during warm mode; and determining whether a command has been sent to turn off the engine, and if so, actively regenerating the LNT; wherein active regeneration is performed by the engine remaining in operation by receiving fuel and with throttling to provide rich exhaust gas.