The drive to control airborne automobile emissions will soon encompass sealed systems for onboard capture and reuse of fuel vapors resulting from refueling. In contrast to current systems that are based in the fuel dispensing pump, onboard refueling vapor recovery (ORVR) systems are intended to capture fuel vapor in a filler-neck sealing system, feed it to a holding canister, and bleed it off into the fuel injection system for combustion in the engine. For these systems to be effective, specialized elastomers will be required for collars, seals, and valve components. Not only must these materials resist degradation caused by fuel and fuel vapors, including those of methanol-containing fuels, they must also function over a wide temperature range.
This paper discusses performance characteristics of fluorosilicone and fluorocarbon materials in an ORVR environment.