Exhaust gas recirculation system for combustion engine detects covering of EGR valve and carries out forced opening of valve only during operation of combustion engine after turning of combustion engine is finished

摘要

The exhaust gas recirculation (EGR) system includes an electronic control unit (ECU) that has a covering detection unit for detecting if an EGR valve is covered when in a closed valve position during the operation of a combustion engine after the turning of the combustion engine is finished. If a covering of the EGR system is detected, the ECU carries out a forced opening of the EGR valve. An opening degree of the EGR valve is set by a control member only during the operation of the combustion engine after the turning of the combustion engine is finished.