  We present a three-way catalyst (TWC) cold-start model, calibrate the model
based on experimental data from multiple operating points, and use the model to
generate a Pareto-optimal cold-start controller suitable for implementation in
standard engine control unit hardware. The TWC model is an extension of a
previously presented physics-based model that predicts carbon monoxide,
hydrocarbon, and nitrogen oxides tailpipe emissions. The model axially and
radially resolves the temperatures in the monolith using very few state
variables, thus allowing for use with control-policy based optimal control
methods. In this paper we extend the model to allow for variable axial
discretization lengths, include the heat of reaction from hydrogen gas
generated from the combustion engine, and reformulate the model parameters to
be expressed in conventional units. We experimentally measured the temperature
and emission evolution for cold-starts with ten different engine load points,
which was subsequently used to tune the model parameters (e.g.~chemical
reaction rates, specific heats, and thermal resistances). The simulated
cumulative tailpipe emission modeling error was found to be typically -20% to
+80% of the measured emissions. We have constructed and simulated the
performance of a Pareto-optimal controller using this model that balances fuel
efficiency and the cumulative emissions of each individual species. A benchmark
of the optimal controller with a conventional cold-start strategy shows the
potential for reducing the cold-start emissions.
