MODEL-BASED TURBOCHARGER CONTROL

摘要

A model-based controlling method of a turbocharger is provided to open a high pressure turbine bypass and to route exhaust flow to a low pressure turbine operating a low pressure compressor stage in order to avoid choke of supercharged air flow resulting from the high pressure compressor stage. An internal combustion system(20) includes an engine(22) having a cylinder, an intake system(24) sucking supercharged air to the engine, and an exhaust system(26) exhausting the exhaust gas. An EGR system(28) re-circulates the exhaust gas from the exhaust system to the intake system. A high pressure turbine stage(32T) operates a high pressure compressor stage(32C). A low pressure turbine stage(34T) operates a low pressure compressor stage(34C). A controlled bypass valve(36T) is parallel to the turbine. A checked bypass valve(36C) is parallel to the compressor. A supercharged air cooler(38) is placed at the lower part of the compressor and the checked bypass valve. The bypass gas passes through an EGR cooler before the gas reaches an EGR valve(40) controlled by a duty cycle signal.