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Shorter new vehicle development time require new engineering methods in the concept and design phase. Therefore methods, which allow an early screening of design alternatives, have been developed and integrated in the design processes. This includes experimental (mostly bench tests) as well as simulation tools. Similar trends can be recognized in the area of exhaust gas aftertreatment. Ever tightening emissions regulations make it necessary in early stages to determine the performance of different aftertreatment concepts. Due to the fact that over 90% of the unconverted emissions occur before the converter is at operating temperature, the heat-up and light-off behavior of the converter is of major importance. In this context a numerical model has been developed to simulate the heat-up and light-off behavior.

Due to the more stringent emissions regulations the catalytic converter has to move closer to the engine. In this hostile environment it is important to have a mechanically durable system, which survives under these severe conditions. This paper shows the evaluation and system design for a close coupled converter. The mechanical durability of this system was proven during an on-road-durability test. During the entire test temperatures were measured inside the converter, at the shell and in the engine compartment to show the thermal management of this system.

Catalytic converter substrates for automobile emission control have to operate under the hostile conditions of the automotive exhaust. This paper will first discuss the mechanical and physical properties to ensure durable mechanical function of the catalytic substrate and converter system. High temperature mechanical and thermal shock substrate requirements and properties will be discussed. The functionality of a catalytic converter is significantly influenced by the catalytic coating. At the same time, substrate characteristics as will be shown, also effect converter functional parameters like back pressure, light-off and conversion efficiency. The importance of the substrate parameters cell shape, cell density and substrate mass and their effect on thermohydraulic parameters like heat- and mass transfer factors for various cell structures and substrates will be presented.