A Two-Time-Scale Infinite-Adsorption Model of Three Way Catalytic Converters

New regulations for emission control make urgent the performance improvement of the cascade engine-TWC (three-way catalytic converters). An important problem is minimization of the harmful emissions during the transient warm-up phase (where the largest amount of dangerous emissions is concentrated). In this perspective, dynamical TWC models, simple enough for on-line computation, are required. Here we present a distributed parameters TWC model suitable for the design and test of warm-up control strategies, obtained by considering an infinite adsorption rate between gas and substrate. The integration algorithm is based partly on a `method of lines' space-discretization, partly on the `method of characteristics' for `quasi linear' hyperbolic PDEs, the separation being allowed by a two time scale analysis of the system. The model has been identified, through a purposely designed genetic algorithm, and validated on experimental data.