Air-to-Cylinder Observer on a Turbocharged SI-Engine with Wastegate

Observers for air mass flow to the cylinder is studied on a turbocharged SI-engine with wastegate. A position change of the wastegate influences the residual gas mass and causes the volumetric efficiency to change, which produces a transient in the air mass flow to the cylinder. Two standard methods of estimating air-to-cylinder are investigated. A new nonlinear air-to-cylinder observer is suggested with two states: one for intake manifold pressure and one for the offset in in-cylinder air mass compared to expected through the volumetric efficiency. The observers are validated on intake manifold pressure data from a turbocharged spark ignited production engine with wastegate.