Abstract: An annular two-phase spring has a plurality of first waves providing a first spring rate and a plurality of second waves providing a second spring rate. The two-phase spring can be used for installing a fuel injector in a fuel injector bore to improve sound performance.

Abstract: A fastener assembly includes a bushing having a flange configured to be urged toward a work-piece, and an isolation spring configured to be positioned between the flange and the work-piece. The isolation spring includes a metal core integrally formed with a rubber coating.

Abstract: A dual-phase spring assembly configured for use with a fuel injector system includes a metal main body and a rubber ring. The main body includes a base integrally connected to a circumferential wall having a radially-canted lip. The base defines a central opening. The radially-canted lip angles away from a center of the main body. The rubber ring secures over the base and to an internal surface of the circumferential wall. The rubber ring covers a ledge of the base, while the radially-canted lip is exposed. The rubber ring is configured to directly abut at least a first portion of the fuel injector system, and the radially-canted lip is configured to directly abut a second portion of the fuel injector system.