Development of Three Way Catalyst (TWC) Ageing Model: Application of Real Driving Emission Condidion 2019-24-0047
Further reduction of vehicles pollutant and CO2 emissions is required to prevent global warming and to improve air quality. The exhaust system is designed to ensure low emission during all life of the vehicle. As catalyst ageing is affecting the catalyst performance, such impact needs to be consider upfront during the design of the fresh catalyst.
Until now, exhaust system design are evaluated based on real tests for each vehicle, using exhaust lines aged on engine test benches or burner benches. This induces major investigation limitations such as: late evaluation in development cycle, high testing and prototyping cost. Usage of Model Based Development approach can be a powerful way to improve this process by allowing system evaluation under several ageing conditions at early development stage.
The present study focuses on modelling of Three Way Catalyst (TWC) ageing to predict the mileage impact on tailpipe emissions. The activity was divided in 4 steps:
1- Development of a detailed TWC for 4 different ageing levels. The impact of ageing is considered by tuning Pre-exponential factors of the reactions Arrhenius laws. The activation energies are not modified, since they are representative of the active site type.
2- Ageing model development: ageing laws are extracted from previous calibrated model considering reaction groups (oxidation, NO reduction, Oxygen Storage Capacity (OSC)…) and Platinum Group Metal (PGM) type.
3- Model validation on driving cycle: Tailpipe emissions are predicted with less than 10% deviation on WLTC.
4- Application and validation to another TWC technology (different amount of PGM and OSC): in that case also, aged TWC emissions prediction is within 10% deviation on WLTC.
The proposed ageing model provides the possibility to predict ageing of any TWC based on existing TWC model calibrated in fresh condition.
Julie Le Louvetel-Poilly, Shankar Balaji, Francois Lafossas
Toyota Motor Europe NV/SA
14th International Conference on Engines & Vehicles