Analytical Processes for High Performance Catalytic Exhaust Systems
The focus of this paper is reciprocating engine exhaust applications. Reciprocating engines produce a tonal exhaust signature, which is dominated by lower frequency energy. Much of the energy is below 300Hz, as compared to turbine exhaust which is broadband in nature with much of the energy spread from 250Hz to 4kHz. Both new and existing reciprocating engine applications typically require a catalyst system to meet the local and federal emission regulations. The integration of catalysts into the exhaust system requires additional structure which is subject to dynamic and thermal inputs. In addition, greater acoustic performance is required in many systems to meet local noise regulations. The low frequency tonal nature of the engine exhaust and its impact on the exhaust system must be considered to avoid resonance issues, achieve high transmission loss and provide a durable system. This paper will discuss the analytical methods used to design the catalytic exhaust system for acoustic, structural dynamic and aerodynamic performance.