Patent ID: 7654076

Claim:
A system, comprising: an electronic control unit connected with an engine for selectively controlling operation of the engine between a rich operating mode and a lean operating mode; a NO x adsorber in fluid communication with a flow of exhaust from the engine; a lambda sensor positioned in fluid communication with the flow of exhaust and the NO x adsorber and connected to the electronic control unit, wherein the lambda sensor is operable to generate a lambda signal indicative of a lambda value associated with the flow of exhaust entering the NO x adsorber; a NO x adsorber manager module executable by the electronic control unit, wherein the NO x adsorber manager module is operative to determine the need to operate in a de-NO x mode or a de-SO x mode, wherein the NO x adsorber manager module includes a NO x lambda profile associated with the de-NO x mode and a SO x lambda profile associated with the de-SO x mode, wherein if the NO x adsorber manager module determines a need exists to operate in the de-NO x mode and the de-SO x mode at the same time the NO x adsorber manager module executes the de-SO x mode if it is feasible given current engine operating conditions, wherein the NO x lambda profile causes the engine to operate at a fixed lambda value and the SO x lambda profile causes the engine to operate at a controllably varying lambda value, and wherein the controllably varying lambda value controllably switches between an upper set point controlling the engine in a lean operating mode for a first predetermined amount of time and a lower set point controlling the engine in a rich operating mode for a second predetermined amount of time.