Method for diagnosing e.g. low-pressure exhaust gas recirculation system of combustion engine for vehicle, involves determining whether system is defective based on calculated amount of exhaust gas re-circulated through system

摘要

The method involves calculating amount of exhaust gas that is re-circulated through a low pressure (LP) exhaust gas recirculation system of an internal combustion engine (1). A determination is made to find whether the LP exhaust gas recirculation system and/or a high pressure (HP) exhaust gas recirculation system is defective based on the calculated amount of exhaust gas that is re-circulated through the LP exhaust gas recirculation system and deviation between desired and actual value of total proportion of the re-circulated exhaust gas.