When the soot loading in the filter reaches a set limit (about 45%) the ECU will release an additive (EOLYS) into the fuel system. The additive reduces the burning temperature of the particulates by 100°C, therefore reducing it from 550°C to 450°C. Once the filter is empty the ECU will switch off the additive. There are two additive systems, one injects the EOLYS directly into the fuel line, the other releases the EOLYS into the fuel tank, this method relies on a pressure sensor on the fuel filler cap.
