METHOD FOR DIAGNOSING THE BYPASS FLAP OF AN EXCHANGER IN AN EXHAUST GAS RECIRCULATION SYSTEM

摘要

The invention relates to a method for diagnosing a failure of an EGR circuit (20) in an engine that comprises an EGR exchanger (22), an EGR valve (21), an EGR exchanger bypass duct (24), and a so-called bypass flap (23a) located upstream from the EGR exchanger (22) and the bypass circuit (24) in order to adjust the proportion of exhaust gases flowing therethrough, wherein the EGR circuit (20) can be activated in a so-called cooled mode in which the flap (23a) is shut and in a so-called bypass mode in which the flap (23a) is open. The method comprises the step of estimating the temperature of the exhaust gases (TsEGRest_byp) at the outlet of the EGR exchanger (22) when the EGR circuit (20) is in the bypass mode.