An extended Kalman observer for the in-cylinder air mass flow estimation

Nowadays, every new gasoline car sold in US, Canada and Europe is equipped with a three-way catalytic converter (TWC) in combination with a fuel control system in order to reduce the pollutant emissions. For the maximum TWC conversion efficiency, the engine control has to furnish a stoichiometric air fuel mixture to the cylinders. For this purpose an estimation of the air incoming into cylinders becomes necessary in every driving condition, not only in steady-state operations, but especially during rapid throttle transients. A conventional speeddensity equation, that evaluates the air incoming engine, depends on the engine speed and intake manifold pressure. The pressure signal is influenced by sensor dynamic and by pumping fluctuations due to periodic moving masses as engine valves. In this work, an Extended Kalman Filter is proposed as observer of the in-cylinder air mass flow rate.