1998-02-23

The Development of BMW Catalyst Concepts for LEV / ULEV and EU III / IV Legislations 6 Cylinder Engine with Close Coupled Main Catalyst 980418

To meet LEV and EU Stage III emission requirements, it is necessary for new catalytic converters to be designed which exceed light-off temperature as quickly as possible.
The technical solutions are secondary air injection, active heating systems such as the electrically heated catalytic converter, and the close coupled catalytic converter. Engine control functions are extensively used to heat the converter and will to play a significant role in the future.
The concept of relocating the converter to a position close to the engine in an existing vehicle involves new conflicts. Examples include the space requirements, the thermal resistance of the catalytic coating and high temperature loads in the engine compartment.
A solution concerning these ever present conflicting objectives has been possible only through the cooperation of all concerned in the consistent application of simulation programs for the cylinder filling process, three dimensional flow calculation, FEM calculation in conjunction with goal-orientated test methods and long range vehicle-related measures. The result, relative to volumetric displacement, is a low-volume, highly effective and economical catalytic converter system.
The layout is currently qualified to fulfill LEV and EU III requirements, and through modifications to the layout parameters, is sufficient for compliance with ULEV and EU Stage IV.

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