Ever more stringent automotive emission regulations and increasingly hostile engine compartment environments are making life tough for fuel system seals, diaphragms and gaskets. Only a few specialty elastomers like DuPont™ Viton® fluoroelastomer can function under such conditions and enable system designers to meet near-zero fuel permeation targets.
There is a striking difference in evaporative emission levels required by yesterday's standards and those being demanded today. There is also a significant difference in severity between legislation now being imposed in Europe and in the USA. It is also probable that the toughest controls of all (those being imposed in California) will eventually become the norm.
At the same time, fuel compositions are changing rapidly to help vehicle manufacturers meet emission limits set by these new regulations. These oxygenate-rich gasolines exhibit higher volatility which can cause swelling, property deterioration and increased permeation through elastomeric materials. The sum effect of tougher legislation, more aggressive engine environments and volatile new fuel compositions is to make life impossible for many conventional elastomers, while opening new opportunities for the few (like Viton®) that function well in such conditions.
The Viton® product line uniquely provides superior permeation over the broadest temperature range. This enables sealing design engineers to make the optimal material selection for improved fuel system seals and gaskets, areas critical for meeting the new regulations. Viton® is being used in many innovative ways in Europe and the USA to meet the new emission regulations.