Resabtors - Advanced Multi-Material Muffler Designs for Clean Air Applications

The development and production of resonators on the charged air side of combustion engines require profound base of knowledge in designing, simulating and the production of such parts in different materials (aluminum, copper, stainless steel and technical plastic). As combustion engines are under constant discussion, this existing knowledge base should be used for other applications within and outside the automotive industry. Very quickly it became apparent that new challenges often require completely new solutions, designs and materials to meet the requirements of flow noise reducing parts. For example, for clean air applications mufflers based on “special treated foams” and “meta-materials” can be introduced. These materials offer new potentials for tuning of the frequency range and allow improved broad banded flow noise attenuation. Such parts are named “Resabtors” in order to take respect of the different flow noise attenuation principles resonation and absorbing. Since in almost all applications the installation space is very limited, it was necessary to combine these two principles into one component. This results into significant challenges to identify the properties of the material and to predict via simulation the noise attenuation level. Finally, these challenges could be solved. A development environment with which a fast and precise design becomes possible does now exist and will be described. Like all sound absorbers placed in a flow, Resabtors can also produce unwanted flow-induced noise. With the help of mechanical models, a deeper understanding of the origin of flow-induced could be achieved. With this knowledge measures were derived in order to reduce the flow induced noise.