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Catalyst Model Reduces Development Time and Improves Calibration Robustness
| Date: | 22/07/2009
| | Title: | Catalyst Model Reduces Development Time and Improves Calibration Robustness |
The selection of appropriate catalyst hardware and the calibration of oxygen storage management functions are critical to optimise catalyst efficiency and to ensure full life emissions conformance. In particular it is critical to avoid fully depleted and saturated conditions which can both give significant pollutant breakthrough. IP has developed and validated a catalyst model to enable much of this task to be carried out analytically thus shortening development cycles and improving robustness.
The model runs in Simulink and interfaces with IP’s existing powertrain / controls simulation. Using real or calculated engine feed-gas and exhaust temperature data, the chemistry in the catalyst is modelled to determine emissions for the gases, THC, NOx, CO and O2. This enables prediction of time resolved tailpipe emissions over either the EU or FTP cycles.
This approach aids the understanding of the effects of key catalyst properties such as cell density, precious metal loading and volume enabling the selection of a suitable catalyst specification during the early development phase and reducing the need for testing of expensive prototype parts.
The model has also proved to be extremely valuable for calibrating oxygen storage management control functions in the EMS, such as downstream AFR control and catalyst neutralisation following fuel cut off events.
The effects of these control parameters in combination with catalyst age and component variability can be readily assessed and the calibration optimised whilst simultaneously reducing testing time and cost.
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