A fuel tank cap including a body, a seal carrier movably positioned within the body, a first seal positioned on the seal carrier and configured for sealably engaging a filler tube opening of a fuel tank, and a second seal positioned on the seal carrier and configured for sealably engaging the body.
1. A method of sealing a fuel tank, comprising:
securing a fuel cap on a fuel tank filler neck;
said fuel cap including a seal carrier including a first seal and a second seal positioned thereon,
wherein said securing causes said seal carrier to move along an elongate axis of said cap, and wherein during said movement of said seal carrier, said first seal moves along and sealingly engages an inner surface of said fuel cap.
2. The method of claim 1 wherein said first seal comprises a seal having a circular cross-sectional shape, and wherein movement of said first seal along said inner surface of said fuel cap comprises rolling movement of said first seal.
3. The method of claim 1 wherein said seal carrier includes a base and an outwardly extending member that defines a seat for said first seal, and wherein said securing causes cantilevered movement of said outwardly extending member so as to movably bias said first seal into sealing engagement with said inner surface of said fuel cap.
4. The method of claim 3 wherein said seat of said seal carrier defines a seat surface positioned, in an unbiased condition, parallel to said elongate axis of said fuel cap, wherein said first seal moves along and simultaneously sealingly engages said inner surface of said fuel cap, and said first seal simultaneously moves along and simultaneously sealingly engages said seat surface of said seal carrier.
5. The method of claim 4 wherein movement of said first seal along said seat surface of said seal carrier comprises rolling movement of an outer circumferential surface of said first seal along said seat surface of said seal carrier.
6. The method of claim 1 wherein said securing causes said seal carrier to move along said elongate axis of said cap so as to compress a biasing element, wherein said biasing element biases said second seal into sealing engagement with said fuel tank filler neck.
7. The method of claim 1 wherein said securing includes twisting said cap on said filler neck along mating helical structures of said cap and said filler neck, and wherein said twisting of said cap causes said seal carrier to move linearly along said elongate axis of said cap.