Variable stiffness fuel rail pulse damper having extended dynamic range

Abstract

A fluid pulse damper having increased dynamic range and sensitivity, being especially useful in suppressing pulsations in the fuel supply rail of an internal combustion engine. The damper is a longitudinal gas-filled plastic pillow having walls formed by opposed flexible short sides and opposed flexible long sides, and includes at least one internal self-contact element, and preferably a plurality of such elements. As the short sides flex, the elements make contact internally, shifting the damper into a different compression regime and extending the pressure/response over an increased range of pressures. A feature of some embodiments is that the inner surface within the contact elements is shifted into tension after the elements make contact, thereby stiffening the damper and increasing the damper's resistance to further deformation. The damper is formed of a plastic such as ultra-high molecular weight polyethylenes, high flow polyetherimides, or tubing grade polyphthalamides.