Electric heater and control system and method for electrically heated particulate filters

A method of operating an exhaust treatment system, comprising:

• providing a particulate matter (PM) filter that filters PM from exhaust gas and that includes N zones that are independent from one another, wherein each of the N zones includes an inlet area that receives a portion of the exhaust gas and wherein N is an integer greater than one;
• activating a first heater element that includes a contact area that heats exhaust gas input to an inlet area of a first one of the N zones until PM in the first zone combusts, wherein the first one of the N zones is axially aligned with a center axis of the PM filter;
• activating a second heater element that includes a second contact area that heats exhaust gas input to an inlet area of a second one of the N zones until PM in the second zone combusts, wherein the second one of the N zones is one of a plurality of zones surrounding the first one of the N zones in a circular arrangement,
• wherein a first ratio of the contact area of the first heater element to the inlet area of the first zone is greater than a second ratio of the contact area of the second heater element to the inlet area of the second zone;
• and
• selectively activating the first heater element and the second heater element in an order based on the first ratio and the second ratio.