초록 ▼

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

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.

대표청구항 ▼

[ What is claimed is:] [1.] A method of controlling the airflow into a compression ignition engine having an exhaust gas recirculation (EGR) passage including a EGR valve connecting an intake manifold and exhaust manifold of the engine, said EGR valve responsive to an EGR valve control signal for re

[ What is claimed is:] [1.] A method of controlling the airflow into a compression ignition engine having an exhaust gas recirculation (EGR) passage including a EGR valve connecting an intake manifold and exhaust manifold of the engine, said EGR valve responsive to an EGR valve control signal for regulating the flow of exhaust gas into said intake manifold, and a variable geometry turbocharger (VGT) including a compressor connected to a turbine, the compressor in communication with the intake manifold and the turbine in communication with the exhaust manifold, said turbine responsive to a turbocharger signal for regulating the intake manifold pressure, the method comprising the steps of:determining a desired intake manifold pressure (p.sub.1d) and desired EGR flow fraction (r.sub.d);detecting the intake manifold pressure (p.sub.1);generating a first deviation (e.sub.p1) between the desired and detected intake manifold pressure;detecting the exhaust manifold pressure (p.sub.2),estimating the EGR flow fraction (r);generating a second deviation (e.sub.r) between the desired and estimated EGR flow fraction;determining an open loop EGR valve control value (V.sub.egr) and an open loop turbocharger value (V.sub.vgt) as a function of the current engine speed and fueling rate;generating proportional and integral feedback gains for the EGR valve (K.sub.p,egr, K.sub.i,egr) and turbocharger turbine (K.sub.p,vgt, K.sub.i,vgt);generating said EGR valve control signal (U.sub.egr) as a function of V.sub.egr, K.sub.p,egr, K.sub.i,egr and e.sub.r ;generating said turbocharger signal (U.sub.vgt) as a function of V.sub.vgt, K.sub.p,vgt, K.sub.i,vgt and e.sub.p1 ;controlling the EGR valve in accordance with U.sub.egr to regulate r; andcontrolling the turbocharger turbine in accordance with U.sub.vgt to regulate p.sub.1.