Predicting the Port Air Mass Flow of SI Engines in Air/Fuel Ratio Control Applications

With the tightening of exhaust emission standards, wide bandwidth control of the air/fuel ratio (AFR) of spark ignition engines has attracted increased interest recently. Unfortunately, time delays associated with engine operation (mainly injection delays and transport delays from intake to exhaust) impose serious limitations to the achievable control bandwidth. With a proper choice of sensors and actuators, these limitations can be minimized provided the port air mass flow can be accurately predicted ahead in time.

While the main objective of this work is to propose a complete AFR controller, the main focus is on the problems associated with port air mass flow prediction.