A Dual-Loop EGR Engine Air-Path Oxygen Concentration Model With Time-Varying Transport Delays

Dual-loop exhaust gas recirculation (EGR) systems can provide control authorities for adjusting the engine in-cylinder gas conditions. However, the transport delay in the EGR air-path makes some simple oxygen concentration dynamic models perform poorly under the transient operating conditions. In this paper, a dual-loop EGR air-path oxygen concentration model considering the time-varying transport delays is developed and a method to calculate the delay time based on the continuity of gas velocity is presented. Simulation validations using a high-fidelity GT-Power 1-D computational engine model show that the developed model can capture the oxygen concentration dynamics during both steady-state and transient operations.