Fluoroelastomer Specialists
Polimotor 2 all-plastic race engine project will use Solvay’s Ryton XK-2340 polyphenylene sulfide (PPS) reinforced resin to injection-mould the assembly’s 46-cm (18-in) fuel rail while seven O-rings fabricated from Tecnoflon VPL 85540 fluoroelastomer (FKM) will seal parts throughout the assembly.
Solvay’s Tecnoflon VPL 85540 fluoroelastomer (FKM) to fabricate seven Orings used to seal the fuel injection assembly.
Led by automotive innovator Matti Holtzberg, the Polimotor 2 project aims to design and manufacture an all-plastic engine for competitive racing later this year, using the polymer technologies to support engine weight-out goals and deliver outstanding reliability and performance under demanding competitive racing conditions.
Holtzberg, who is also president of Composite Castings, based in West Palm Beach, Florida, said: “While the fuel rail and O-ring applications demanded materials with a higher degree of performance, Solvay’s unmatched selection of specialty polymers offered us a versatile range of candidate solutions to work from.”
“While certain grades of Amodel PPA would have made a suitable metal alternative for the fuel rail, we felt Ryton XK-2340 PPS delivers a better balance of high-temperature chemical resistance and dimensional stability. The Tecnoflon VPL O-ring, in turn, not only offers excellent sealing force at high temperatures, it maintains superior flexibility and fuel compatibility even in extreme cold,” He added.
When placed under high pressure, FKM materials experience an upward shift in their glass transition temperature (Tg). A standard fuel-resistant FKM with -10°C (14°F) Tg under normal atmospheric conditions, for example, would shift to +10°C (50°F) Tg in a high-pressure, 1,000 bar environment.
In practical terms, this shift can compromise the material’s flexibility and sealing function, resulting in performance problems for a race car engine, especially on a cold start condition. Solvay’s Tecnoflon VPL series are low-temperature peroxide curable FKM grades that offer the lowest cold temperature flexibility and best fuel compatibility among all fluoroelastomers. More specifically, Tecnoflon VPL 85540’s -40°C (40°F) Tg will help ensure the O-rings in the Polimotor 2 engine will perform reliably within design limits even under high pressure.
Molding Concepts in Sterling Heights, Michigan, built the tooling and injection molded the
fuel rail using Solvay’s Ryton XK-2340, a 40 per cent glass-fibre reinforced PPS compound. As its name implies, the fuel rail channels fuel to the Polimotor 2 engine’s four injector nozzles. In conventional race and production vehicles, this component would commonly be a six-part welded steel assembly. However, replacing steel with a high performance thermoplastic not only allowed the fuel rail to be injection moulded as a single piece, it also enabled 25 to 30 per cent reduction in part weight.
Read more: Polimotor 2 chooses Solvay’s Ryton PPS and Tecnoflon FKM for demanding fuel injection system
