Method to determine the oxygen storage capacity of a catalytic converter of an exhaust gas system of an internal combustion engine

Abstract

A method to determine the oxygen storage capacity of a catalytic converter of an exhaust gas system of an internal combustion engine is described; wherein the exhaust gas system is provided with an exhaust duct, along which catalytic converter is housed; a lambda sensor housed along exhaust duct downstream of catalytic converter to detect the concentration of oxygen in the exhaust gases; and an exhaust gas after-treatment system having a burner designed to introduce exhaust gases into exhaust duct; wherein inside burner there is defined a combustion chamber, which receives fresh air through a first supply circuit and fuel from a second supply circuit. The method comprises a step in which to recognise that internal combustion engine is in a stop phase or in a slow running mode; a step in which to control the first and the second supply circuit so as to obtain a given objective lambda value, in particular other than one; a step in which to determine a delay with which lambda sensor detects the change in objective lambda value; and a step in which to calculate the oxygen storage capacity of catalytic converter by means of said delay.