Patent ID: 8631644

Claim:
A method of operating an engine that is configured to post inject a quantity of fuel into a combustion chamber and comprises a Diesel Oxidation Catalyst (DOC) having an inlet and an outlet, comprising: determining an open loop post injection quantity q post — OL of fuel as a function of a target temperature T Otarget for said outlet; determining a current temperature T O at said outlet; determining, for said current temperature T O , a closed loop post injection quantity q post — CL of the fuel needed for correcting said open loop post injection quantity q post — OL , for determining a correct post injection fuel quantity q post needed to match a desired DOC heat release related to the target temperature T Otarget ; and operating said engine with the correct post injection fuel quantity q post ; wherein determining the closed loop post injection quantity q post — CL provides for the setting of a target difference (dQ o /dt−dQ i /dt) target between outlet heat power dQ o /dt and inlet heat power dQ i /dt for said Diesel Oxidation Catalyst (DOC) as a function of a temperature T i of said Diesel Oxidation Catalyst (DOC) and of exhaust gas mass flow dm/dt at the inlet and outlet of said Diesel Oxidation Catalyst (DOC).