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A complex automotive muffler consisting of multiple chambers, perforated baffles and pipes with perforated sections is simulated with both a linear and non linear solver in regard to duct acoustics. The goal is to be able to predict the acoustic performance of the muffler and correctly assess the effect of any changes to the muffler configuration. The linear solver is a frequency domain code using the transfer matrix method to predict the acoustic performance. The non linear solver is a time domain code using a finite volume method to predict the flow distribution and pressure drop across the muffler. A recently developed linear acoustic model for perforates has been applied to the perforated sections of the automotive muffler. This includes different configurations of the muffler both with and without flow. The perforate model with flow requires the correct flow distribution throughout the muffler in terms of through flow and grazing flow for each perforated section.

The pressure drop as well as the overall lifetime of wall flow diesel particulate filters is strongly influenced by the capability of storing non-combustible ash. One approach to reach low pressure drops and long filter lifetimes is the application of optimized channel geometries. This study presents a comprehensive simulation approach for filters with asymmetrical channel structures in the presence of soot and ash. The wall flow model, soot loading and regeneration approaches are discussed with all model equations. The soot filtration model distinguishes between the regimes of depth and cake filtration. The regeneration model takes into account soot regeneration reactions, catalytically supported soot reactions and catalytic wall reactions. The simulated pressure drop of filters with different channel diameters at different operating conditions is compared to measured values. The predicted pressure drop due to depth and cake filtration is compared to experimental data.

The present work introduces an extended particulate filter model focusing on capabilities to cover catalytic and surface storage reactions and to serve as a virtual multi-functional reactor/separator. The model can be classified as a transient, non-isothermal 1D+1D two-channel model. The applied modeling framework offers the required modeling depth to investigate arbitrary catalytic reaction schemes and it follows the computational requirement of running in real-time. The trade-off between model complexity and computational speed is scalable. The model is validated with the help of an analytically solved reference and the model parametrization is demonstrated by simulating experimentally given temperatures of a heat-up measurement. The detailed 1D+1D model is demonstrated in a concept study comparing the impact of different spatial washcoat distributions.