Moreover, blow-moulding technology enables greater flexibility in the integration of application-specific connections, such as those required for resonators, sensors or the discharge of gases. Together, the combination of lower weight, more efficient production and assembly, and the integration of variable functionality, provides for a significant cost advantage over the earlier model, which was produced using glass-fibre reinforced nylon and elastomers.

Used on the “cold” side of the engine, the air duct, consisting of two Hytrel sections measuring 300 mm and 400 mm respectively, is one of the first mono-material solutions of its kind in Germany. “Despite the ambitious nature of this development, we succeeded, with DuPont’s support, in combining high functionality with high cost-efficiency,” comments Thorsten Riechelmann, project manager at Mahle. “For example, finite element calculations conducted by DuPont helped us to optimise wall thickness in line with the given pressure and temperature conditions (2 bar absolute pressure at -40 °C to +100 °C). The same simulations from DuPont also generated very precise assembly data. This enabled us, for example, to optimise the integrated bellows at a sufficiently early stage to ensure that the high levels of deformation, necessary due to the limited assembly space, and the pressure levels required to install it, were within an acceptable range.” Riechelmann continues: “Overall there was a strong correlation between the values provided by DuPont and those which resulted from actual component testing. We also appreciated greatly the technical support available from DuPont’s technical centre in Geneva with regard to three-dimensional blow moulding. From there we were able to source valuable advice on how to conduct both energy-saving and reliable processing, which simplified the start of serial production considerably.”

Hytrel HTR4275 is a specially-modified grade for use in blow-moulding, with an increased melt viscosity, a hardness of 55 Shore D and a relatively high stiffness of 170 MPa at 23 °C and 60 MPa at 100 °C.

The Mahle Group is amongst the 30 largest automotive suppliers and is the world’s leading producer of components and systems for the combustion engine and its peripherals. Mahle employs around 45,000 people at over 100 production facilities and eight R & D centres in Stuttgart, Northampton, Detroit (Farmington Hills, Novi), Tokyo (Kawagoe, Okegawa), Shanghai and São Paulo (Jundiaí). In 2008, the company achieved a turnover of over EUR 5 billion.