Aftertreatment Control for Detection of Fuel Contaminant Concentration

A system for detecting when an engine is combusting fuel containing more than a sulfur concentration threshold value, the system comprising:

• a selective catalytic reduction (SCR) module including an SCR catalyst;
• at least one sensor for detecting at least one of
• a NOx concentration downstream of a NOx abatement catalyst module and
• a NH3 concentration downstream of the NOx abatement catalyst module,
• the at least one sensor linked to a controller;
• the controller configured to calculate at least one of a NOx conversion ratio by the NOx abatement catalyst module and a degree of ammonia slip;
• the controller further configured to initiate desulfation of the SCR catalyst if at least one of a conversion ratio or a degree of ammonia slip fails to meet at least one predetermined criteria;
• the controller further configured to record when a desulfation is complete;
• the controller configured to determine a desulfation request time (DRT) between completion of a desulfation and initiation of a new desulfation;
• the controller configured to increment a frequent desulfation counter (FDC) each time the DRT is greater than a predetermined minimum time and less than a predetermined maximum time;
• the controller configured to initiate a fuel sulfur alarm signal when the FDC reaches a NOx conversion ratio threshold value.

A power system comprising:

• an engine including a manifold exhaust passage in communication with a selective catalytic reduction (SCR) module including an SCR catalyst, the NOx abatement catalyst module in communication with an exhaust outlet;
• at least one sensor for detecting at least one of
• a NOx concentration downstream of the NOx abatement catalyst module and
• a NH3 concentration downstream of the NOx abatement catalyst module,
• the at least one sensor linked to a controller,
• the controller configured to calculate at least one of a NOx conversion ratio by the NOx abatement catalyst module and a degree of ammonia slip;
• the controller further configured to initiate desulfation of the SCR catalyst if at least one of the conversion ratio or the degree of ammonia slip fails to meet at least one predetermined criteria;
• the controller further configured to record when a desulfation is complete;
• the controller configured to determine a desulfation request time (DRT) between completion of a desulfation and initiation of a new desulfation;
• the controller configured to increment a frequent desulfation counter (FDC) each time the DRT is greater than a predetermined minimum time and less than a predetermined maximum time;
• the controller configured to initiate a fuel sulfur alarm signal when the FDC reaches a NOx conversion ratio threshold value;
• and
• the controller further configured to generate an equipment failure signal if the DRT is more than the predetermined maximum time.