Combining resistance to temperature extremes with good performance in demanding fuel environments. DuPont serves in a wide variety of elastomer fuel hose applications.
Using advanced DuPont™ Viton® fluoroelastomer veneered hose technology, a customer has commercialized a turbo hose using the fluoroelastomer for the critical inner layer. Viton® has replaced silicone or fluorosilicone, both of which delaminated through swelling in hot fuel vapor at +200°C, resulting in permeation and weeping.
Viton® has met extensive flex and aging requirements, following a rigorous hot flex rig test run for several weeks under high vibration. The customer also reports excellent adhesion of Viton® to the braided DuPont Nomex® aramid reinforcement layer.
For turbo hose applications with temperatures below 165°C, DuPont™ Vamac® is a cost effective alternative.
A hose manufacturer has been able to reduce hydrocarbon emissions from a co-injection molded fuel filler neck hose to below 0.01 g per day, thanks to a 0.6 mm inner layer of Viton®. This is a dramatic improvement in emissions compared with a competitive NBR design that achieves approximately a 1g per day performance.
The customer reports that its proprietary forming process allows for better tolerance control, greater design flexibility and easier assembly. The greatest need is projected for the USA due to extensive use of metal fuel filler pipes that require flexible filler neck hose connections.
Refrigerant restandardization has left one component of this comfort accessory system unchanged: Neoprene is the preferred tubestock polymer for dependable performance in contact with coolant gas/liquid streams.