STANYL® PA46 IN TUMBLE VALVES SUPPORT EFFICIENCY

Stanyl®, a high-performance polyamide 46 (PA46) resin from DSM Engineering Plastics, was chosen for the production of tumble valve bearings for the latest generation of the V6 and V8 engines of a high value german car producer. Tumble valves are an integral part of the manifold, optimizing the air flow in the combustion chamber. It is the first time that such tumble valves have been produced by assembly molding and Stanyl® played an important role in making this possible.

With the in-mold assembly technique, components are assembled inside the mold in a two shot (2K) process. This results in significant cost savings compared to traditional processes in terms of assembly, tooling, and machinery. For in-mold assembly to work, a combination of materials is required which can meet both the in-mold process demands as well as perform reliably under the operating conditions throughout the life of the engine. In the molding process, Stanyl® has outstanding stiffness at high temperatures – even close to its melting point – which enables 2K overmolding without distortion of the initial molding. As the assembly has a bearing function, free movement of the two components is required after production, requiring that no adhesion occurs between the two materials during the molding process and that shrinkage coefficients are such that free movement is maintained after molding and at engine operating conditions and temperatures up to 150°C.

In addition, wear and friction behavior of the component materials is very important. The tumble valve bearings have to resist high loads which are constantly operating at high frequency when the engine is running. Good wear and friction properties play an important role in the lifetime of the component itself and subsequently the engine. A grade, selected from the Stanyl® portfolio of materials that are optimized for stiffness and improved tribological performance, gave the right performance against the mating material in the assembly (PPS).

“The success of this full plastic tumble valve proves the excellence of plastics in reducing costs while providing functionality”, said Thomas Lunow, Technical Engineering Specialist for DSM. “This solution also demonstrates the reliability of Stanyl® in such challenging applications”.

The tumble valve optimizes the air flow in the combustion chamber and ensures a faster and uniform distribution of the air fuel dispersal. This results in a faster burning speed and more efficient combustion. In its turn, that supports significant improvements on the engine’s performance as well as lowering fuel consumption of the car, typically by 0.2 liters of gasoline per 100 km for the same engine power. The use of tumble valve also leads to NVH (Noise Vibration Harshness) improvements.

Schneegans GmbH a specialist for two component production and responsible for development and realizing the total production concept (Emmerich am Rhein, Germany), the molder of these thermoplastic tumble valves, uses Stanyl® in its challenging assembly molding. Stanyl® played an important role by enabling Schneegans to successfully execute this in-mold assembly technique in the production of such a highly demanding application. The development of this innovative tumble valve system by Schneegans was realized in partnership with Pierburg and Mercedes Benz.

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