A method of thermal protecting a particulate filter of an internal combustion engine

A method of thermal protecting a particulate filter (280, fig.1) of an internal combustion engine, eg from being thermally stressed by uncontrolled soot burning inside the filter during active regeneration, comprises the steps of: determining (step S100) a value of a particulate filter temperature T; determining (step S105) a value of a soot quantity Q trapped inside the particulate filter, and limiting (steps S115/S120) an oxygen quantity that can be supplied to the particulate filter on the basis of the determined value of T and Q. The oxygen quantity may be limited by limiting (step S115) the number of engine cylinders that can be unfuelled, and/or by limiting (step S120) the air/fuel ratio supplied to one or more cylinders. Steps S115/S120 may be preceded by estimation (step S110) of the maximum oxygen mass flow rate through the filter without causing excessive thermal stresses. The filter temperature may be measured; the trapped soot quantity may be estimated.