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Comparison of Measured and Predicted Three-Way Catalyst Conversion Efficiencies under Dynamic Air-Fuel Ratio Conditions
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Abstract
Results of three-way catalyst (TWC) conversion efficiency measurements are presented which demonstrate the effects of dynamic operation. In one series of measurements, the time-averaged conversion efficiencies were determined for the case in which the TWC was subjected to a series of complex air-fuel ratio (A/F) waveforms. The measured efficiencies are compared to predicted efficiencies determined from the superposition of the TWC response to the individual sinusoidal components comprising the complex waveform. This comparison shows discrepancies for CO in the lean region, and for HC and NOx in the rich region.
In a second series of measurements, the instantaneous conversion efficiencies were determined for a square wave A/F waveform using a timed-sampling technique. The results of these measurements illustrate the effects of O2 storage, the enhancement of CO conversion due to the water-gas shift reaction, and the enhancement of NOx conversion during the rich portion of the A/F waveform. The square wave A/F results are used to partially explain the time-averaged results.
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Citation
Shulman, M., Hamburg, D., and Throop, M., "Comparison of Measured and Predicted Three-Way Catalyst Conversion Efficiencies under Dynamic Air-Fuel Ratio Conditions," SAE Technical Paper 820276, 1982, https://doi.org/10.4271/820276.Also In
References
- Blumberg P. N. Wu H. Auiler J. E. “A Methodology for Evaluation and Optimization of Three-Way Catalyst Based, Low NOx Emission Control Systems.” Paper 810273 presented at SAE International Automotive Congress and Exposition Detroit February 1981
- Su E. C. Montreuil C. “Oxygen Storage Capacity of Three-Way Catalysts - Part I: Measurement by Pulse Injection Technique.” Ford Engineering and Research Technical Report No. SR78-64 July 1978
- Hamburg D. R. Hyland J. E. “A Vaporized Gasoline Metering System for Internal Combustion Engines.” Paper 760288 presented at SAE International Automotive Congress and Exposition Detroit February 1976
- Hamburg D. R. Shulman M. A. “A Closed-Loop A/F Control Model for Internal Combustion Engines.” Paper 800826 presented at SAE Passenger Car Meeting Dearborn June 1980
- Hamburg D. R. Shulman M. A. Aquino C. F. Palmer M. D. “Frequency Response Characterization and Compensation of the Ricardo Equivalence Ratio Monitor.” Paper 810752 presented at SAE Passenger Car Meeting Dearborn June 1981
- Sell J. A. Herz R. K. Monroe D. F. “Dynamic Measurement of Carbon Monoxide Concentrations in Automotive Exhaust Using Infrared Diode Laser Spectroscopy.” Paper 800463 presented at SAE International Automotive Congress and Exposition Detroit February 1980
- Kaneko Y. Kobayashi H. Komagome R. Nakagami T. Fugui T. “Catalyst Systems Development.” Paper 770197 presented at SAE International Automotive Congress and Exposition Detroit February 1977
- Throop M. J. Hamburg D. R. “Transient Engine Emissions and Dynamic Three-Way Catalyst Conversion Measurements Using a Timed Sampling Method.”
- Herz R. K. “Dynamic Behavior of Automotive Catalysts. 1. Catalyst Oxidation and Reduction.” Ind. Eng. Chem. Prod. Res. Dev. 20 3 1981
- Otto N. C. Bettman M. Montreuil C. N. “Development of a Mathematical Model for the Steady State Performance of Three-Way Catalysts.” Paper 30E presented at AICHE Summer National Meeting Detroit August 1981
- Otto N. C. Kress J. W. “Three-Way Catalyst Behavior Under Conditions of Transient A/F Fluctuations.” Paper 30A presented at AICHE National Meeting San Francisco November 1979