A stand made of Zytel for the hot exhaust systems ends
The injection moulding is always leaving a gap for amazing applications. Anvisgroup of Bad Soden-Salmünster, Germany, working in cooperation with Volkswagen, has developed the first support of catalytic converter for cars manufactured with a thermoplastic engineering. Due to its placement - very close to the engine, where temperatures can reach up to 175 ° C, high static and dynamic forces, moisture and chemical combinations - steel plates had been considered always as irreplaceable for such applications.
It sometimes seems that the mere fact of being with the word "irreplaceable" gives designers more courage to substitute metal or other materials for the plastic. Anvisgroup has proven that these plates of steel are not irreplaceable, to develop innovative support of two pieces of glass fibre reinforced nylon-based DuPont Zytel and gum. Since the middle of the year 2006, design has been tested in the extreme hot of the exhaust systems of all new vehicles of the Volkswagen Golf (PQ35) range.
The manufacture of the new support begins with a molding by injection of the crossbar with Zytel. In a second phase of production, are molded rubber bushings, made of EDPM (for diesel engines and gasoline engines small) or silicone VMQ more resistant to heat (for high-performance gasoline engines). Finally, aluminum bearings, necessary to ensure the brakes are assembled by means of adjustment by encliquetaje. Mounted between the exhaust system and the catalyst, the piece made up of two components provides support flexible and mitigating system of exhaust in the x direction, and to absorb the static and dynamic loads in directions 'and' and 'z'. Thus, it prevents, for example, shocks to the front of the exhaust system in the event of a sudden halt, which otherwise might damage sensitive valves flexible metal to avoid change of cargo movements and vibrations between the material and the exhaust system.
Exhaustive tests, carried out by Anvisgroup, have shown that Zytel 70G35HSL, a PA66 stable to hydrolysis with 35 percent of its weight made up of glass fibres, meets the requirements of the OEM for the reliability of the entire life cycle of the vehicle. "The component was subject to the kind of extreme conditions that one can only experience in real life if you drive a car and a heavy trailer to uphill along a road with potholes for hundreds of kilometers," explains Gerhard HeckmannHead of the Group of products for mounting and dismounting of exhaust in Anvisgroup systems. "The results of our tests confirm that, even in these circumstances, support made of fibre glass reinforced Zytel continues its performance impeccably." "Moreover, the new brake from the catalytic converter offers high levels of security during its entire lifecycle."
In addition, the new design offers major advantages: firstly, the polymer component weighs only 165 g by what is considerably lighter than its twin of metal, which weighs 300 g. Second, it facilitates cost savings during manufacturing because, for example, the protection of the surface is no longer necessary to prevent corrosion. "With the completion of this project we have been able to implement first mounting of a polymeric material for the hot ends of an escape module." "Therefore, there is nothing to prevent the development of an alternative polymer for the cold end also", concludes Heckmann.
Solutions for cars
Anvisgroup develops functional solutions for Dynamics of vehicles, comfort and security. Its product range includes components for the chassis, suspension systems power-plant, Assembly and disassembly of elements/TMD of exhaust systems. As a global innovator in solutions of acoustics and vibration for vehicle control, Anvisgroup and 2200 employees have managed a profit of 260 million euros in 2006.
