One dimensional three way catalyst model for control and diagnostics
AssigneeFord Global Technologies, LLC
InventorsPankaj Kumar, Imad Hassan Makki
Life of this patent
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Abstract
A method comprising adjusting a fuel injection amount based on a fractional oxidation state of a catalyst, the fractional oxidation state based on reaction rates of grouped oxidant and reductant exhaust gas species throughout a catalyst and a low-dimensional physics-based model derived from a detailed two-dimensional model to obtain a one-dimensional model averaged over time and space that accounts for diffusion limitations in the washcoat and accurately predicts emissions during cold start.
Claims18
An engine exhaust method, comprising:
- determining a fractional oxidation state of a catalyst based on reaction rates of each of an oxidant group comprising NOx, O2, H2O and CO2 exhaust gas species and a reductant group comprising CO, HC, H2, H2O exhaust gas species throughout a catalyst, a one-dimensional model averaged over space and time, and mass balance and energy balance equations for a fluid phase and a washcoat of the catalyst;
- and
- adjusting a fuel injection amount based on the fractional oxidation state.
A system comprising:
- a catalyst positioned in an engine exhaust system;
- and
- a controller including non-transitory instructions stored in memory to:
- determine a catalyst activity, a total oxygen storage capacity, and a
- fractional oxidation state of the catalyst based on a catalyst model that tracks a change in a concentration of each of a reductant group comprising CO, HC, H2, H2O exhaust gas species and an oxidant group comprising NOx, O2, H2O and CO2 exhaust gas species concentrations through the catalyst, the catalyst model comprising a one-dimensional model averaged over space and time, as well as mass balance and energy balance equations for a fluid phase and a washcoat of the catalyst;
- indicate catalyst degradation if the catalyst activity or the total oxygen storage capacity is below a threshold;
- and adjust a fuel injection amount if the fractional oxidation state is outside a threshold range.
A method for an engine including a catalyst, comprising:
- determining a catalyst activity based on an error between predicted exhaust gas sensor output and measured
- exhaust gas sensor output;
- applying the catalyst activity to a catalyst model and applying concentrations of each of an oxidant group comprising NOx, O2, H2O and CO2 exhaust gas species and a reductant group comprising CO, HC, H2, H2O exhaust gas species at an inlet of the catalyst to the catalyst model to determine a total oxygen storage capacity and a fractional oxidation state of the catalyst, the catalyst model including a one dimensional model averaged over space and time, as well as mass balances and energy balances of a fluid phase and a washcoat of the catalyst;
- adjusting a fuel injection amount maintaining a desired air fuel ratio based on the total oxygen storage capacity and the fractional oxidation state of the catalyst;
- and
- indicating catalyst degradation if the catalyst activity or the total oxygen storage capacity is less than a threshold.
Dependencies are inferred from the claim text.