Control method and apparatus for turbocharged diesel engines having exhaust gas recirculation

摘要

A method and apparatus of controlling the airflow into a compression ignition engine having an exhaust gas recirculation (EGR) system and a variable geometry turbocharger (VGT). The control strategy includes the steps of measuring the intake manifold pressure and exhaust manifold pressure, and using these values, estimating the EGR flow fraction. The EGR flow fraction is then used in a proportional plus integral feedback control loop to generate position commands for the EGR valve. Similarly, the intake manifold pressure signal is used in a proportional plus integral feedback control loop to generate position commands for the VGT. In this way, the EGR valve is used to regulate the EGR flow fraction to a desired value and the VGT turbine is used to regulate the intake manifold pressure to a desired value.