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Online Estimation of the Oxygen Storage Level of a Three-Way Catalyst
Technical Paper
2004-01-0525
ISSN: 0148-7191, e-ISSN: 2688-3627
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English
Abstract
Very stringent limits for exhaust gas emissions as well as high claims for onboard diagnosis (OBD) of the three-way catalytic converter (TWC) demand a sophisticated control and observer strategy which can both further reduce the exhaust gas emissions and also estimate the relevant parameters allowing to monitor the decreasing performance of the TWC over its lifetime. The most crucial parameter and state, respectively, are widely believed to be the oxygen storage capacity (OSC) and the relative oxygen level (ROL) of the TWC. The TWC's performance decreases with a diminishing OSC. Therefore, an accurate estimation of the OSC can be used for OBD. Keeping the ROL at an optimal level by means of control enhances the TWC's performance significantly, even during transients of the air/fuel ratio imposed by the driver.
In order to monitor both the ROL and the OSC, an observer has been derived from a complex TWC model. The observer consists of an extended Kalman filter (EKF), which estimates the ROL of the TWC from the exhaust gas mass flow, the temperature and the lambda-sensor signal upstream of the TWC. Additionally, the gas composition and the signal of a sensor downstream are estimated in order to close the loop for the EKF. The EKF also estimates the OSC by means of online estimation.
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Auckenthaler, T., Onder, C., and Geering, H., "Online Estimation of the Oxygen Storage Level of a Three-Way Catalyst," SAE Technical Paper 2004-01-0525, 2004, https://doi.org/10.4271/2004-01-0525.Also In
References
- Ammann, M. “Abgasoptimale Lambdaregelung eines Ottomotors” Diploma thesis at the Measurement and Control Laboratory ETH Z¨urich 1999
- Auckenthaler, T. Onder, C. Geering, H. “Modelling of a solid-electrolyte oxygen sensor” SAE paper 2002-01-1293 2002
- Auckenthaler, T. Onder, C. Geering, H. “Control-oriented investigation of switch-type air/fuel ratio sensors” 15 th IFAC World Congress Barcelona 2002
- Auckenthaler, T. “Modelling and Control of Three-Way Catalysts” 2004
- Bozek, J. W. Evans, R. Tyree, C. D. Zerafa, K. L. “Operating Characteristics of Zirconia Galvanic Cells (Lambda Sensors) in Automotive Closed-Loop Emission Control Systems” SAE paper 920289 1992
- Dictor, R. “A Kinetic Study of the Water-Gas Shift Reaction over Rh/Al2O3 Catalysts” Journal of Catalysis 106 458 463 1987
- Ingram, G. Gopichandra, S. “On-line Oxygen Storage Capacity Estimation of a Catalyst” SAE paper 2003-01-1000 2003
- Jobson, E. Hjortsberg, O. Andersson, S. Gottberg, I. “Reactions Over a Double Layer Tri-Metal Three-Way Catalyst.” SAE paper 960801 1996
- Onder, C. H. ETH Züurich 1993
- Robert Bosch GmbH 23th Vieweg Wiesbaden 1999
- Rogers, J., W. Baer, D., R. “Interfacial and Processing Sciences Annual Report 1999” Environmental and Molecular Sciences Laboratory, Pacific Northwest National Laboratory Richland, Washington
- Welch, G. Bishop, G. “An Introduction to the Kalman Filter” http://www.cs.unc.edu/∼welch/media/pdf/kalman_intro.pdf 2002
- Zarchan, P. Musoff, H. “Fundamentals of Kalman Filtering: A Practical Approach” 190 Progress in Astronautics and Aeronautics AIAA 2000