Systems and methods for desulfation of catalysts included in aftertreatment systems

An aftertreatment system for reducing constituents of an exhaust gas having a sulfur content, comprising:

• a selective catalytic reduction catalyst;
• and
• a controller configured to:
• determine a NOX conversion efficiency of the selective catalytic reduction catalyst;
• in response to the NOX conversion efficiency being less than a predetermined threshold, cause a temperature of the selective catalytic reduction catalyst to increase to a first regeneration temperature that is greater than or equal to 400 degrees Celsius and less than 550 degrees Celsius;
• cause the temperature of the selective catalytic reduction catalyst to be maintained at the first regeneration temperature for a first time period;
• after the first time period, cause the temperature of the selective catalytic reduction catalyst to increase to a second regeneration temperature greater than the first regeneration temperature and less than 550 degrees Celsius;
• and
• cause the temperature of the selective catalytic reduction catalyst to be maintained at the second regeneration temperature for a second time period.

An aftertreatment system for reducing constituents of an exhaust gas having a sulfur content, comprising:

• a selective catalytic reduction catalyst;
• and
• a controller configured to:
• determine a NOX conversion efficiency of the selective catalytic reduction catalyst;
• in response to the NOX conversion efficiency being less than a first predetermined threshold, cause a temperature of the selective catalytic reduction catalyst to increase to a first regeneration temperature that is greater than or equal to 400 degrees Celsius and less than 550 degrees Celsius;
• cause the temperature of the selective catalytic reduction catalyst to be maintained at the first regeneration temperature for a first time period;
• in response to the NOX conversion efficiency being less than a second predetermined threshold that is less than the first predetermined threshold or a time interval between subsequent regeneration events at the first temperature being less than a time interval threshold, cause the temperature of the selective catalytic reduction catalyst to increase to a second regeneration temperature that is equal to or greater than 550 degrees Celsius;
• cause the temperature of the selective catalytic reduction catalyst to be maintained at the second regeneration temperature for a second time period;
• and
• in response to the NOX conversion efficiency being less than a third predetermined threshold that is less than the second predetermined threshold, or the time interval between subsequent regeneration events at the second temperature being less than a time interval threshold, generate a fault code.