As global regulations on automotive emissions tighten, original equipment manufacturers (OEMs) are tasked with not only reducing exhaust emissions but also mitigating evaporative emissions from fuel systems. This transition in regulatory focus requires controlling fuel vapor losses caused by refueling, diurnal temperature changes, running losses, permeation through components, and hot soak conditions. Chemours Viton™ fluoroelastomers (FKM) are the go-to solution for automotive OEMs looking to achieve superior sealing performance and meet the latest regulatory standards for evaporative emissions compliance.

Why Evaporative Emissions Matter

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Worldwide regulatory standards such as the United States CARB Tier 3/LEV III and European 6d-TEMP-EVAP-ISC mandate strict limits on the release of fuel vapors into the atmosphere. Evaporative emissions stem from the following five primary sources.
 

To combat these emissions, low-permeation materials are critical in fuel system components such as fuel sender seals, fuel filler neck seals, fuel hoses and lines, gaskets, O-rings, and cam lock and lock nut mechanisms.

Why Choose Viton™ for Unmatched Permeation Resistance

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Historically, traditional elastomers like nitrile rubber (NBR) have been used for sealing applications; however, due to new regulatory standards, it is no longer a viable option due to its limited permeation resistance. Viton™ FKM materials exhibit exceptional resistance to fuel permeation, even in the presence of ethanol-blended fuels (e.g., E10).
 

Key advantages of Viton™ for fuel system sealing include the following:

• Unmatched fuel permeation resistance to help OEMs meet stringent regulatory limits
• Outstanding low-temperature sealing that ensures reliable performance, even at temperatures as low as −32°C (−26°F)
• Long-term retention of mechanical properties that maintains integrity under heat, fuel exposure, and over extended periods
• Compatibility with emerging fuels, as Viton™ performs well with ethanol, diesel, biofuels, and eFuels

Excellent Sealing Performance in Fuel Applications

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Chemours offers a portfolio of Viton™ FKM grades, each optimized for specific fuel system demands. In laboratory tests, Viton™ grades such as GLT, GFLT, AL, A, and F significantly outperformed NBR in permeation resistance when tested with E10 fuel blends.

 

 

Excellent Low-Temperature Properties

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Chemours offers a portfolio of Viton™ FKM grades, each optimized for specific fuel system demands.

Selecting the Right Viton™ Grade

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Chemours offers a portfolio of Viton™ FKM grades, each optimized for specific fuel system demands.
 

These grades allow engineers to tailor solutions to meet specific environmental conditions, regulatory demands, and fuel formulations.
 

Conclusion

By choosing Viton™ fluoroelastomers, OEMs gain not only superior sealing performance but also the backing of a partner with deep regulatory expertise, global manufacturing capabilities, and a commitment to sustainability. Click the link below today to learn about which Viton™ grade works best for your application!