Approach for aftertreatment system modeling and model identification
A system and approach for catalyst model parameter identification with modeling accomplished by an identification procedure that may incorporate a catalyst parameter identification procedure which may include determination of parameters for a catalyst device, specification of values for parameters and component level identification. Component level identification may be of a thermal model, adsorption and desorption, and chemistry. There may then be system level identification to get a final estimate of catalyst parameters.
1. An aftertreatment system comprising:
a catalyst device configured to treat an output from an engine exhaust; and
a controller including a catalyst model for the catalyst device, the controller configured to control operation of the catalyst device based on the catalyst model and the catalyst model comprises:
a thermal model component;
an adsorption and desorption component;
a chemical reaction component; and
a global component; and
wherein:
the thermal model component includes parameters representing heat transfer of the catalyst device, the heat transfer of the catalyst includes heat transfer from gas to monolith, heat transfer from monolith to housing, and heat transfer from housing to ambient;
the adsorption and desorption component includes parameters that incorporate a storage of chemical species for reaction; and
the chemical reaction component includes parameters that incorporate a reaction mechanism for chemical reactions.
2. The system of claim 1 , wherein the controller is configured to:
obtain values of the parameters of the catalyst model from the vendor data; and
automatically estimate values of the parameters of the thermal model with on-engine data or flow bench data when reaction heat is suppressed.
3. The system of claim 2 , wherein the controller is configured to:
estimate the parameters of the adsorption and desorption component independently when flow bench data are available; and
estimate the parameters adsorption and desorption component together with virtually all chemical reactions when flow bench data are not available.
4. The system of claim 3 , wherein the chemical reaction component incorporates separable chemical reactions, wherein one reaction of the separable chemical reactions takes place at a time such that each chemical reaction can be isolated from other chemical reactions of the separable chemical reactions.
5. The system of claim 4 , wherein the chemical reaction component can further incorporate one or more inseparable chemical reactions.
6. The system of claim 4 , wherein:
steady state data can be used in a steady state catalyst model parameter identification;
the steady state catalyst model parameter identification based on steady state data is an estimate for a transient data catalyst model parameter identification based on transient data; and
transient data can be used in the transient data catalyst model parameter identification.