FULLY INTEGRATED COMPOSITE EXHAUST SYSTEM

摘要

Stringent CO_2 emission regulations for car manufacturers have resulted in engine downsizing,hybrid drivelines and lighter automotive bodies. The required weight reduction, usuallyaccomplished by optimizing steel thickness, can also be achieved by the utilization of compositematerials and integrated structural elements/subsystems. An example of such a system is the fullcompositeexhaust system described in this paper. The proposed exhaust system consists of 3concentric layers: the outer, load carrying composite tube, a combination of insulation layers,and an inner liner to protect the fragile insulation layer against abrasion. The combination ofinsulation layers does not only provide thermal protection, but it additionally attenuates sound ina very effective way. Due to the lower outer shell temperature and the reduced sound level, heatshields (in some cases) and conventional mufflers become obsolete. Depending on the enginelocation and the number of omitted elements, the weight reduction ranges from 17% to even85%. The exhaust system can either be produced by enclosing the internal layers into twomolded shells that are bonded to each other, or by overbraiding the liner-insulation layerarrangement, for example with robotic equipment.