Methods for responding to sensor failures on EGR/VGT engines

摘要

Methods for controlling an internal combustion engine 12 in the face of sensor failures and mechanical faults include generating accurate substitute values for use by the engine control logic when variable geometry turbocharger (VGT) 52 and exhaust gas recirculation (EGR) 66 system related sensors are diagnosed as having failed during operation. A sensor for which a substitute value is generated may include barometric pressure 84. The value of barometric pressure may be obtained by commanding the VGT to zero boost whilst the engine is idling and using the boost pressure sensor 76 reading as the value of barometric pressure in the control logic. Further sensors for which substitute values may be generated include boost pressure 76, turbo speed 82, compressor inlet temperature 80, compressor outlet temperature 78. The mechanical fault may be with an EGR valve.