E-047
A non linear observer for fuel film dynamics into the intake manifold of a spark
ignition engine
Authors: I. Arsie, C. Pianese, G. Rizzo
Affiliation: Department of Mechanical Engineering, University of Salerno - Italy
Abstract
A non linear observer, based on an extended Kalman filter, is presented for the estimation
of the non linear fuel film dynamics into the intake manifold of a spark ignition
engine. In order to meet the stringent limits imposed on automotive exhaust emissions,
electronic engine control systems have to constrain Air-Fuel ratio in a narrow band
around the stoichiometric value, since even a small excursion results in a large
degradation of catalyst conversion efficiency. A two states dynamic model is used
to describe liquid and vapour fuel mass flows into the intake manifold, accounting
for both the partial impingement of the injected liquid fuel on the manifold walls
and the evaporation process. The application of an extended Kalman filter allows
to deduce a minimum error estimate of both model states (liquid and vapour fuel mass)
and parameters (evaporation time constant and injected liquid fraction impinging
the wall) utilizing the knowledge of system dynamics and the UEGO sensor measurement
at exhaust location. The observer has been tested on a set of 35 Air-Fuel ratio dynamic
transients showing a good prediction level with respect to engine fuel flow and Air-fuel
ratio. Moreover the trend of estimated model parameters vs. operating conditions
is consistent with the physical phenomena taking place in the region interested by
the fuel injection process.
Ivan Arsie
University of Salerno
Dept. of Mechanical Engineering
Fisciano (SA), 84084, Italy
tel:fax:+39.089.964037
tel:work:+39.089.964080
arsie@mbox.diima.unisa.it