Control Oriented Modeling of the Dynamics in a Catalytic Converter
The legal amount of emissions that vehicles with spark ignited
engines are allowed to produce are steadily reduced over time. To
meet future emission requirements it is desirable to make the
catalytic converter work in a more efficient way. One way to do this
is to control the air-fuel-ratio according to the oxygen storage
level in the converter, instead of, as is done today, always trying
to keep it close to stoichiometric. The oxygen storage level cannot
be measured by a sensor. Hence, a model describing the dynamic
behaviors of the converter is needed to observe this level. Three
such models have been examined, validated, and compared.
Two of these models have been implemented in Matlab/Simulink and
adapted to measurements from an experimental setup. Finally, one of
the models was chosen to be incorporated in an extended Kalman
filter (EKF), in order to make it possible to observe the oxygen
storage level online.
The model that shows best potential needs further work, and the EKF
is working with flaws, but overall the results are promising.}
Jenny Johansson and Mikaela Waller
2005
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Last updated: 2021-11-10