Mercury Marine Verado outboard engine captures all the value of engineering polymers
A highly successful metal replacement application for Mercury Marine is a new supercharger outlet elbow/duct made of DuPont™ Zytel® HTN PPA from DuPont Performance Polymers. The intermediary duct for the Mercury Marine Verado outboard engine captures all the value of engineering polymers – parts consolidation, high-temperature resistance, lower weight and reduced cost – with no performance tradeoffs. The high-performance duct is the first use of a thermoplastic in a pressure-charged air handling duct for outboard engines.
“In making the switch, we were able to easily adopt Zytel® HTN in this demanding application with no issue; that is, with no loss of durability or overall performance,” explained Scott Westpfahl – Mercury Marine program manager for stern drive engines.
The thermoplastic duct, which delivers charged air from the supercharger to the charged air cooler, operates in an extremely hot environment (up to 175˚C). Zytel® HTN51-series resin, a high-temperature resistant PPA, meets the stringent thermal requirements, replacing thin-gauge 1018 formed steel which also required a heat sleeve for added thermal protection. The 7-in-long, 2.4-in dia. thermoplastic duct doesn’t require a heat shield and provides a cooler touch.
“This is a breakthrough development that required extensive technical support from the get-go,” said Dino Tres, development programs manager – DuPont Performance Polymers, who directed the company’s technical support. “DuPont offered Mercury extensive processing expertise in injection molding and blow molding in the early development phases and then delivered vital material selection and computer simulation assistance (including finite element analysis) to optimize the design.”
The conversion from metal to Zytel® HTN PPA reduces the number of parts (six to five) and lowers associated part costs. The plastic design eliminates the corrosion layer and a related painting step which was required on the steel version and also offers more pleasing aesthetics (better surface appearance). Also eliminated was a failure of the metal to repeatedly cut the rubber cuffs at the end of the duct.
Known for its exceptional temperature and load resistance, Zytel® HTN resin also provides 15 percent faster cycles than competitive PPA materials. The material’s high-glass transition temperature of 145˚C facilitates better flow and faster part ejection.
The supercharger elbow duct was manufactured by using a rotating core to produce a gentle, curved design which helped minimize pressure drops. The injection molding process also produced parts with greater dimensional stability than those made of formed steel.
The plastic supercharger outlet duct is used on all four- and six-cylinder models of Mercury Marine’s flagship Verado supercharged outboard engine. Mercury was an early adopter of engineering thermoplastics in outboard engine components and has increasingly used DuPont materials for their unique benefits over traditional materials like metal.
“Our vision for the Verado was to develop a more automotive-like engine in terms of fast acceleration and unbeatable torque and we turned to DuPont because of its innovation and experience working with the auto industry, especially in powertrain and transmission systems,” Westpfahl said. “In short, we wanted 8-cylinder performance from a 6-cylinder engine for greater efficiency and we wanted a materials development partner with leadership in that area.”
DuPont Performance Polymers specializes in application development, operating globally and using a broad range of high-performance materials and technology to help customers in the global aerospace, appliance, automotive, consumer, electrical, electronic, industrial, sporting goods and other diversified industries deliver high-quality, cost-effective systems and components.
DuPont Performance Polymers is the largest, most globally networked nylon manufacturer exclusively focused on engineering polymers. Operating compounding sites in 13 countries, DuPont is the only nylon 6,6 producer to own and operate world-scale, continuous-polymerization assets in all three regions of the world.
DuPont (www.dupont.com) is a science-based products and services company. Founded in 1802, DuPont puts science to work by creating sustainable solutions essential to a better, safer, healthier life for people everywhere. Operating in more than 90 countries, DuPont offers a wide range of innovative products and services for markets including agriculture and food; building and construction; communications; and transportation.
Click here for high resolution image of the Mercury Marine Verado engine
Click here for high resolution image of the Mercury Marine Supercharger Outlet/Duct of DuPont™ Zytel® HTN PPA Resin