Method of evaluating a soot quantity accumulated in a selective catalytic reduction washcoated particulate filter (SDPF)

摘要

A method of evaluating a soot quantity accumulated in a Selective Catalytic Reduction washcoated particulate filter (SPDF) 520, of an internal combustion engine (110, fig 1) comprises the steps of: - determining an urea quantity value (U_inj) to be injected by a urea injector; - determining a NOx quantity value at an inlet (Inlet_NOx) of the selective catalytic reduction washcoated particulate filter; - determining a temperature value (Inlet_temp) at the inlet of the selective catalytic reduction washcoated particulate filter; - determining a mass flow value (EMF) of an exhaust gas; - using a map correlating the urea quantity value (U_inj), the NOx quantity value (Inlet NOx), the temperature value (Inlet_temp) and the mass flow value (EMF) to a correction value (SQcorr) of a soot quantity; - correcting an estimated value (SQest) of the soot quantity using the correction value (SQcorr) in order to obtain an evaluated value (SQeval) of the soot quantity. The method takes the continuously regenerating trap (CRT) effect into account in an SDPF architecture.