Adaptive desulfation and regeneration methods for lean NOx trap

摘要

An adaptive method is used for LNT desulfation and regeneration. The desulfation method involves adapting the amount of sulfur loading to trigger a desulfation event in accordance with the current adsorption capacity of the LNT. The method involves monitoring the current sulfur loading and the current LNT adsorption capacity. This data is used to calculate a loading amount “trigger”, whose value varies over the LNT lifetime. Whenever this trigger amount is reached, a desulfation event is performed. The regeneration method is similar, with the baseline data and loading threshold being determined by NOx loading rather than sulfur loading.

主权项

1. A method of controlling desulfation of a lean NOx trap (LNT), the LNT operable to adsorb NOx and to become loaded with a loading amount of sulfur until a desulfation event is performed, comprising:
within a control unit,
monitoring a current sulfur loading amount;monitoring a current NOx adsorption capacity; andusing the current sulfur loading amount and the current NOx adsorption capacity to calculate a variable sulfur loading trigger amount; and operating an engine to perform a desulfation event when the current sulfur loading amount meets the variable sulfur loading trigger amount.