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Methods for Fast Catalytic System Warm-Up During Vehicle Cold Starts
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English
Abstract
During vehicle cold start, emissions, mass flow rates, and catalytic converter space velocities vary by orders of magnitude. Therefore, catalytic exhaust control systems must be designed to operate at high efficiency almost from the moment of engine start-up. Catalysts must reach their operating temperature as quickly as possible. Therefore, the utility of different methods for improving the warm-up characteristics of catalytic systems is illustrated.
A very elegant method to speed the warm-up is the use of the engine itself as a “preheater” for the catalytic converters. High exhaust gas enthalpy to raise exhaust system mass up to its operating temperature is obtained by the use of extreme spark retard, stochiometric mixtures, and fully opened throttle. Intensive studies to investigate the effects of concurrent changes of spark timing and air/fuel mixtures on exhaust gas temperature, enthalpy, NOx and HC emissions are discussed.
Finally, NOx catalyst characteristics are dealt with, because the NOx catalyst is the first in a dual-bed catalytic system. The NOx catalyst should have high activity, low ignition temperature, and good warm-up performance. If the NOx catalyst has a fast warm-up rate, this would result even in a significant improvement in the warm-up characteristic of the HC/CO bed.
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Citation
Bernhardt, W. and Hoffmann, E., "Methods for Fast Catalytic System Warm-Up During Vehicle Cold Starts," SAE Technical Paper 720481, 1972, https://doi.org/10.4271/720481.Also In
References
- Campau R. M. “Low Emission Concept Vehicles,” SAE Paper No. 710294 January 1971
- Meguerian G. H. Lang C. R. “NO x Reduction Catalysts for Vehicle Emissions Control,” SAE Paper No. 710291 January 1971
- Roth J. F. “Copper-Based Auto Exhaust Catalysts: Mechanisms of Deactivation and Physical Attrition,” Paper Monsanto Company St. Louis, Missouri 63163 1971
- Campau R. M. Taylor R. E. “The IIEC-A Cooperative Research Program for Automotive Emission Control,” Paper No. 17-69 34th Midyear Meeting of the API's Division of Refining Chicago, Illinois May 12 1969
- Bernhardt W. E. “Kinetics of Nitric Oxide Formation in Internal Combustion Engines,” Paper C 149/71 Conference on Air Pollution Control in Transport Engines of the Institution of Mechanical Engineers Solihull, England November 9-11 1971
- Kuo J. C. Lassen H. G. Morgan C. R. “Mathematical Modeling of Catalytic Converter Systems,” SAE Paper No. 710289 January 1971
- Dwyer F. G. Jagel K. I. “HC/CO Oxidation Catalysts for Vehicle Exhaust Emission Control,” SAE Paper No. 710290 January 1971