A unique design for automotive sender seals to comply with PZEV regulations
Fuel sender seals are one of the most critical emissions paths in automotive fuel systems. But an innovative seal development by Poly-Nova Technologies Inc, using DuPont Performance Elastomers (DPE) Viton® fluoroelastomer, is expected to change all that, and comply with the latest PZEV (partial zero emission vehicle) evaporative emissions requirements.
In a departure from conventional all-rubber sender seals, Poly-Nova, of Ontario, Canada, a leading custom molder of elastomers, has developed a unique two-component seal for the fuel tank/fuel sender unit interface for gasoline fueled automobiles. The design exploits the low-temperature resistance and vapor-tight sealability of Viton® fluoroelastomer, overmolded with a permeation-resistant plastic insert.
Innovative automotive fuel sender seal developed by Poly- Nova Technologies Inc, exploits the low-temperature resistance and vapor-tight sealability of Viton® fluoroelastomer overmolded with a permeation resistant plastic insert, and is expected to comply with the latest PZEV evaporative emissions requirements. |
"With the drive for zero hydrocarbon (HC) emissions, all sealing interfaces in the fuel system have become a huge focus of attention in the automotive industry. The sender seal is one of the largest emission leak paths currently in the vehicle, partly because today's rubber seals do not meet PZEV evaporative requirements of 5 mg/day HC) due to HC permeation through the rubber," says Rick Valeriote, President and CEO of Poly-Nova.
"To meet the ultra-low emissions challenge, we have developed a composite seal design that enables a more efficient use of high performance, specialty materials — Viton® fluoroelastomer and DuPont Minlon® mineral filled nylon 6.6 resin. Currently undergoing rigorous permeation and fuels resistance testing, this sender seal is expected to meet the target of 1-2 mg/day evaporative HC emissions — well below existing US LEV II and Euro 4 requirements, and compliant with PZEV," Valeriote adds.
Sender O-ring seals have a tough job to do. They must seal a large (typically some 5 inch / 13 cm) hole in the gas tank, demanding an O-ring of some 15 inches / 38 cm in circumference. Each vehicle requires at least one seal, and many new vehicles with 'saddle' tanks have two. That's a lot of surface to seal against aggressive automotive fluids.
With Viton® fluoroelastomer right at the fuel tank/fuel sender unit interface, and plastic forming the added permeation barrier, Poly-Nova's solution is unusual, particularly in comparison with other all-rubber sender seals currently installed.
(L to r) Phil Baber, Vice-President Engineering at Poly-Nova, and Eric Thomas, Senior Technology Engineer for DuPont Performance Elastomers discuss the potential of an innovative new fuel sender seal of Viton® fluoroelastomer overmolded with plastic, which, unlike current all-rubber sender seals, is designed to meet the target of 1-2 mg/day evaporative HC emissions — below existing US LEV II and Euro 4 requirements, and compliant with PZEV. |
"Poly-Nova has specified Viton® GF-S made with Advanced Polymer Architecture for its sender seal development due to its easy processing and outstanding end-use performance in automotive fuel system sealing applications," says Eric Thomas, Senior Technology Engineer for DuPont Performance Elastomers, and technology leader for the overmolding development with Viton®.
"We find Viton® GF-S very injection-molding friendly. The flow path to fill the large sender seal mold is extremely long, but the excellent flow and demoulding characteristics of Viton® have enabled us to optimize seal design." says Phil Baber, Vice-President Engineering at Poly-Nova.
Viton® made with APA is the result of USD 50 million investment in proprietary new polymerization and curing technology. APA polymers deliver significant improvements in processing and final part performance and meet rigorous automotive fuel system and powertrain sealing requirements, particularly in providing a better barrier to evaporative emissions, and enhanced resistance to new fuel compositions and temperature extremes.
Applications for APA polymers in the automotive industry include fuel system seals and hoses, and air intake and engine oil gaskets. They are also specified for O-rings, valve seals, pump diaphragms, process system tubing and other sealing parts for the chemical, aerospace and semiconductor industries. For more information, click on www.viton.com.
Poly-Nova's fuel sender seal design is currently undergoing 2000 hours product testing in a variety of automotive fuels, including Fuel 'C' — the most aggressive. This data is expected to be available early 1st quarter 2007, followed by independent third party shed testing. Commercialization is expected end 2007, with innovative seals destined for new '09 model year vehicles.
"Poly-Nova is already a significant player in this market. By thinking out of the box and beyond traditional concepts, we expect the sender seal project to be a major event for the company, and one that will present leading-edge opportunities for our customers," says Rick Valeriote.
The company invites discussions with fuel system OEM's, Tier 3-4 fuel valve manufacturers, Tier 1 tank suppliers and major automotive manufacturers to review the future potential of the new-concept sender seal with Viton® fluoroelastomer and plastic. Contact Poly-Nova at www.poly-nova.on.ca
Poly-Nova Technologies, Inc., a privately owned company established in 1993, and operating from a 33,000 sq.ft state-of-the-art facility in Guelph, Ontario, Canada, is a custom molder of elastomers, with specialization in overmolding of plastic and metal inserts.
Poly-Nova is a leader in technology development and has expertise in materials formulation, design and manufacturing engineering to customer requirements. Key business fields are the automotive, appliance and power distribution industries.
In the automotive industry, the company is an important supplier of overmolded sealing components to major North American fuel valve manufacturers, for application in fuel vapor and emissions management systems.
Viton® is a trademark of DuPont Performance Elastomers.
DuPont is a registered trademark of DuPont and its affiliates.
Minlon® is a registered trademark of DuPont.
