Control-oriented time-varying input-delayed temperature model for SI engine exhaust catalyst

This paper proposes a model for the internal temperature of a SI engine catalyst. The modeling approach is grounded on a one-dimensional distributed parameter model, which is approximated by a time-varying input-delay system whose dynamics parameters (time constant, delay, gains) are obtained through a simple analytic reduction procedure. Following recent works, the distributed heat generation resulting from pollutant conversion is shown here to be equivalent to an inlet temperature entering the system at a virtual front inside the catalyst. The gain of this new input introduces a coupling to account for the conversion efficiency. Relevance of this model is qualitatively supported by experimental data.