Innovative Capless Refueling Seal Success for GM

Mark Conlee, Engineering Director at Morgan Polymer Seals

MORGAN POLYMER SEALS PARTNERS WITH ITW TO DEVELOP CUSTOM RUBBER SEALING APPLICATION FOR CADILLAC CT6

Morgan Polymer Seals announced today the successful design and implementation of a specialized capless refueling seal, supplied to General Motors to eliminate fuel vapors from escaping the fill tube of their Cadillac CT6. Dubbed internally as the “mechanical seal,” this application was developed in collaboration with Tier 1 automotive supplier, Illinois Tool Works (ITW).

The capless refueling system on the Cadillac required a custom solution due to the limitations of the compact fuel vapor canister built into the vehicle. Typically, the solution would be to install a larger canister, but the body architecture for the CT6 could not accommodate a larger component. So engineers at the two companies designed a solution to seal directly on the fuel nozzle with a double-lip seal. And this solution led to another challenge: by sealing directly on the nozzle, the system would require an over-flow door seal to be integrated within the constraints of the capless refueling assembly.

Engineering Director, Mark Conlee elaborates,

“External constraints on the vapor canister necessitated a thin door to seal against the over-molded lip on the over-flow feature of the mechanical seal. This design created predictable, but unwanted deflection of the plastic substrate from the spring force. To compensate for this deflection, we designed the seal lip to follow a 3D contour with varying height. By profiling the seal in this way, we assured the seal’s integrity against the uniformly distributed sealing force. Furthermore, the fluorocarbon material had to meet a -40C TR10 ‘glass transition’ temperature requirement, which can be challenging to injection mold. Still, we successfully molded the seal and achieved a world-class scrap rate of less than 1%.”

Morgan’s engineers credit their close collaboration with ITW’s engineers and GM’s technical experts, whom all contributed their experience with a broad range of materials, seal design, and manufacturing expertise.

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