| 摘要 |
A method of diagnosing efficiency of an aftertreatment system 270 of an internal combustion engine 110, wherein the aftertreatment system comprises an exhaust duct 275, an oxidation catalyst 280 (e.g. a diesel oxidation catalyst - DOC) disposed in the exhaust duct, and a particulate filter 285 (e.g. a diesel particulate filter - DPF) disposed in the exhaust duct downstream of the oxidation catalyst. The method comprises the steps of: executing post injections of fuel into the engine to perform a regeneration process of the particulate filter; determining a value of an exhaust gas temperature in the exhaust duct between the oxidation catalyst and the particulate filter; adjusting a quantity of post injected fuel by means of a controller that receives as input a difference between the determined value of the exhaust gas temperature and a target value thereof; identifying a malfunctioning of the oxidation catalyst if, during the regeneration process, the value of exhaust gas temperature is below a predetermined threshold value, and contemporaneously a value of a parameter indicative of the post injected fuel quantity is above a predetermined threshold value. |
