摘要：Both existing new and expected future legislation for I.C. engine exhaust gas emissions are leading to change the automotive components with a view to limit the greenhouse effect and the atmospheric pollution. Major effort will lead to a weight reduction of cars in order to reduce fuel consumption. A high efficiency catalytic exhaust system will be a must in the next few years.Exhaust manifolds in stainless steel are considered an interesting solution able to satisfy both weight saving and emission constraints. Innovative technologies that substitute the traditional cast iron solutions are:Hydroforming making manifolds by welding thin walled stainless steel tubes that have been shaped by hydraulic pressure Precision vacuum casting making manifolds as a single near net shape thin wall casting.The employ of these technologies makes it possible to reduce the weight of a manifold by up to 40% and, thanks to the use of stainless steel, still support high optimal exhaust gas temperatures above 800 °C giving best catalytic converter performance results.
