Polimotor 2 engine features 3D-printed automotive plenum

  • PA6 powder grade designed specifically for laser sintering processes (SLS)
  • 3D-printed plenum with comparable performance to injection molded part
  • Project aims to develop an all-plastic engine weighing only 63-67kg

The Polimotor 2 engine will feature a 3D printed plenum chamber fabricated through selective laser sintering (SLS). The specific material used to fabricate the plenum is a Sinterline Technyl polyamide 6 (PA6) from Solvay Engineering Plastics, a powder grade reinforced with 40 percent glass beads to enhance dimensional stability.

Polimotor 2: the next-generation, all-plastic engine

The Polimotor 2 project is led by legendary automotive innovator Matti Holtzberg who aims to design and manufacture a next-generation, all-plastic engine for competitive racing in 2016.

“Like the original Polimotor engine concept developed during the eighties, Polimotor 2 is all about highlighting trailblazing polymer technologies, and their potential for revolutionizing automotive performance and manufacturing,” said Holtzberg, who is also president of Composite Castings, LLC, based in West Palm Beach, Fla. “The plenum in the Polimotor 2 concept shares the same basic injection-molded design from the original engine. But we found that a 3D printed version fabricated with Sinterline Technyl PA6 technology could perform just as reliably in an engine designed to withstand the rigors of competitive racing.”

Formulated to leverage the benefits of 3D printing for nylon components

Based on the same resin chemistry as Solvay’s Technyl polyamides, Sinterline PA6 powders are formulated to leverage the benefits of 3D printing for nylon components. Laser sintering and other 3D-printing processes improve productivity by quickly converting digital designs into functional parts without the time or cost required to first build a molding tool and prototype. Thus, they can significantly accelerate the time-to-market for OEMs and Tiers.

Selective Laser Sintering (SLS): laser fuses PA6 powder layer by layer

Laser sintering applies the energy from a high-precision laser scanner to fuse the PA6 powders, layer by layer, until they form a finished, highly functional three-dimensional part with good mechanical and thermal properties. Because parts are printed in successive layers, laser sintering can also quickly produce components that integrate complex internal features and functions.

Polimotor 2 all-plastic engine will feature a 3D printed plenum chamber

The Polimotor 2 all-plastic engine will feature a 3D printed plenum chamber fabricated with Solvay Engineering Plastics’ Sinterline Technyl PA6 powders (source: Solvay Engineering Plastics)

The automotive plenum part

An automotive plenum is the pressurized chamber that uniformly distributes the air flow between an engine’s inlet and cylinders. The plenum in the Polimotor 2 engine will share similar specifications to those in today’s production-scale automobiles, which are typically injection-molded nylon with 2-3 mm wall thickness to withstand the 2-4 bars of positive air pressure inside.

Parts printed from Sinterline Technyl PA6 powders are capable of performing reliably in a conventional metal turbocharged engine, where radiant temperatures can reach as high as 121°C (250°F). Notably, however, the plenum in the Polimotor 2 concept will encounter comparably lower temperatures between 66°C (150°F) and 93°C (200°F), due to the low thermal conductivity of the engine’s largely plastic composition.

Project aims to develop an all-plastic engine weighing only 63-67kg

The Polimotor 2 project aims to develop an all-plastic, four-cylinder, double-overhead CAM engine that weighs between 63-67 kg (138 to 148 lb), or about 41kg (90 lbs) less than today’s standard production engine. In addition to the current plenum application, Holtzberg’s program will leverage Solvay’s materials to develop up to ten engine parts, including water pump, oil pump, water inlet/outlet, throttle body, fuel rail and other high-performance components.

Solvay is the principal material sponsor for the Polimotor 2 project. In addition to Sinterline Technyl PA6 powders, Solvay materials targeted for use encompass polyphthalamide (PPA), polyetheretherketone (PEEK), polyaryletherketone (PAEK), polyphenylsulfone (PPSU), polyphenylene sulfide (PPS) and VPL fluoroelastomers.

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