The Future of Heterogeneous Catalysis in Automotive Applications; “Turbulent“ Catalysts for Spark- and Compression Ignition Engines"

Authors

Dipl.-Ing. W. Maus, Dipl.-Ing. R. Brück, EMITEC Gesellschaft für Emissionstechnologie mbH, Lohmar

Year

2005

Print Info

Fortschritt-Berichte VDI, Reihe 12, Nr. 595

Summary

The development of catalyst technology for automotive application started in the early sixties with the adoption of highly efficient pellet catalysts from chemical engineering techniques. This catalyst type showed very high mass transfer rates, which were comparable to those of turbulent flow conditions. Nevertheless, catalyst beds made of pellets like these, were condemned to fail due to abrasion caused by mechanical vibration and gas pulsation. In order to increase durability, metallic substrates have been used which were common in the oil refinery industry. Those also failed because they disassembled due to the lack of foil joint technologies in order to provide a monolithical honeycomb structure. Ceramic honeycomb structures have been developed later, whose straight channels also were coated with the catalytic material. Due to their smooth channels the chemical reaction was limited by the poor mass transfer rate to the channel wall. Actual developments have resulted now in substrate constructions, which make use of turbulence effects in the channel flow. Hereby the conversion of regulated pollutants is improved due to higher mass transfer rates equivalent to turbulent flow conditions. In the subsequent chapters the basic steps of car application will be described and test results will be presented.

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