Advanced Catalyst System for the Audi RS 6, 8 Cylinder, 4.2 ltr, 331 hp with LEV Certification

Authors

Dipl.-Ing. M. Ganz, Dipl.-Ing. S. Hackmayer, quattro GmbH, Neckarsulm; Dipl.-Ing. C. Kruse, Dipl.-Ing. A. Reck, Emitec GmbH, Lohmar

Year

2004

Print Info

Fortschritt-Berichte VDI, Reihe 12, Nr. 566

Summary

The sporty Audi RS6, TLEV with a V8 bi-turbo engine has been in production since 2002. The 4.2-litre, 450 hp high performance engine produces outstanding torque of 560 Nm. In order to respond to continuing demand in the US, 2004 sales had to comply with LEV legislation. The resulting 50 % reduction in emissions required both engine modifications and an innovative catalytic converter system without changes to the exhaust back pressure and the available space. The car is fitted with two close-coupled and two underfloor catalytic converters with a metal substrate structure. The Audi RS6, LEV is world wide the first mass produced vehicle to use a completely new catalytic converter system, the "PE design". The metal foils used in the pre-catalytic converter have 8-mm perforations [1]. The so-called PE foils permit the crossflow of the exhaust gases from one cell channel into adjacent channels. Because of the perforations and a thinner foil the heat capacity of the metal substrate could be reduced by half compared to the TLEV version. As a result the catalytic converter reaches its operating temperature faster from a cold start. The cold start properties are supported by the design of a converter mantle with integrated air gap insulation, which minimises heat loss particularly in the front section important during cold starts. In combination with the engine modifications and the coating developed by Engelhard Technologies at the same time it was possible to keep emission levels well below the LEV limits even after a 60,000- mile endurance test under realistic driving conditions.

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