Exhaust gas aftertreatment systems

A method for regenerating a particulate filter coupled downstream of an SCR catalyst, the SCR catalyst coupled downstream of an oxidation catalyst, the method comprising:

• providing an indication that the particulate filter regeneration is required;
• in response to said indication, adjusting an amount of a reductant in an exhaust gas mixture entering the oxidation catalyst to provide a first particulate filter operating range;
• and
• adjusting an amount of said reductant in an exhaust gas mixture entering the particular filter to provide a second particulate filter operating range.

An exhaust gas aftertreatment system for an internal combustion engine exhaust, the system comprising:

• an SCR catalyst;
• a reductant delivery system including at least a heating element, said reductant delivery system coupled downstream of said SCR catalyst;
• a particulate filter coupled downstream of said reductant delivery system;
• and
• a controller providing an indication that filter regeneration is required, and in response to said indication raising a temperature of said particulate filter above a regeneration temperature by injecting a predetermined amount of a reductant and air into said reductant delivery system and adjusting a heating element temperature such that a mixture of said reductant and air combusts inside said reductant delivery system.