Patent ID: 8006480

Claim:
A method of operating a power generation system, comprising: operating a diesel engine to produce a lean exhaust comprising NO X ; passing the lean exhaust through an exhaust aftertreatment system comprising a lean NO X trap; operating the exhaust aftertreatment system in lean phases during which the lean NO X trap adsorbs a portion of the NO X from the exhaust; and selectively denitrating the lean NO X trap in rich phases based on both a first and a second criteria being met; wherein the first criteria is a threshold amount of NO X stored in the NO X trap, a threshold saturation of the NO X trap, or remaining a threshold NO X storage capacity remaining in the NO X trap; the second criteria is one or more measurements of NO X concentration in the exhaust showing that the lean NO X trap, or the lean NO X trap in combination with one or more other devices, has reached a threshold level for NO X removal efficiency or effectiveness at limiting NO X emissions; during the lean phase if only one criteria is met, the other criteria is recursively examined and the lean phase continued at least until the other criteria is also met; and the rich phases comprise providing an overall rich exhaust-reductant mixture to the lean NO X trap, whereby the lean NO X trap releases and reduces stored NO X .