A fuel pump assembly has a bushing defining a pumping chamber, a plunger,
a cam follower piece, and a compliance device for absorbing noise by
increasing either or both of a hydraulic and/or a mechanical compliance
of the fuel pump assembly. The compliance device may includes a spring
washer or a press-fit spring. The pump bushing and/or plunger may include
a cavity as the compliance device for increasing dead volume, the cavity
being in fluid communication with the pumping chamber via an orifice. A
deflectable or movable mechanism is positioned within a cavity for
increasing dead volume, and a solenoid varies a diameter of the orifice.
The moveable mechanism includes a poppet valve having a switching
pressure related to engine speed. A vehicle includes an engine,
transmission, fuel rail, and a fuel pump assembly configured with at
least one compliance device for absorbing a hydraulic noise component.