Thermal Front Propagation of Fast Igniting Catalytic Converters

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The problems of ignition and propagation of a thermal front in a catalytic converter will be studied theoretically and experimentally in order to gain a better understanding of the factors controlling these phenomena. A preliminary theoretical analysis utilizing non-linear dynamics and bifurcation theory will be extended to analysis of more complex models. Experimentally, macroscopic thermal wave propagation will be investigated via infrared thermography studies on unsupported model substrates, studies on supported model catalysts, and studies on a section of a catalytic converter. In addition, the issue of communication between two reactive spots (communications between individual catalyst particles) will be similarly experimentally investigated. Finally, a new radial catalytic converter design which is predicted on the basis of preliminary analysis to have particularly desirable characteristics as regards fast ignition and thermal front propagation will be studied further. Evolving air pollution regulations for automobiles have the effect of requiring that catalytic converters come up to full effective operation with a minimal time delay subsequent to engine startup, making the development of catalytic converters with minimal ignition delay and rapid thermal front propagation highly important. Accordingly, a major goal of this program is development of an understanding of the critical phenomena (fundamental mechanisms) which will lead to design of more efficient fast-igniting catalytic converters without the onerous requirement of external heating sources (an alternative approach to "fixing" the cold startup emissions problem.