Managing Increasing Exhaust System Variants for Passenger Vehicles 2018-01-1557

In all major markets, the legislation on emissions (CO2, NOx, and PM) and on pass-by noise limits have been drastically lowered over the last years and will be even lower in the near future. This will have an enormous impact on the design of future passenger cars, their powertrains, and finally their exhaust systems with an inherent cost penalty. Moreover, the individual market requirements in Europe, Asia and the Americas differ in some respect often calling for individual variants. The increasing number of vehicle models and platform derivatives e.g. sedan, hatchback, coupe, convertible, sports utility vehicle, cross-over etc. leads to a huge variety of exhaust systems even within a single OEM platform let alone a whole OEM product portfolio. This causes significant effort in development, tooling, manufacturing, part handling, and logistics. The Active Noise Cancellation technology (ANC) has been investigated in the automotive industry for many years. The basic principles are well understood and active engine mounts as well as in-cabin active noise cancellation are in series production for a few years. For exhaust muffler systems, several studies at prototype level have demonstrated technical feasibility and resulted in substantial benefits for acoustical performance and sound design. Moreover, advantages in package space, weight, and backpressure have been demonstrated for different engines. In this publication, an overview of different active exhausts compared to conventional cold-end systems will be given and the advantages in development time, reduction in the number of variants and possible cost impacts will be analyzed.