Valve assembly for fuel system and method

摘要

A valve assembly in an internal combustion engine fuel system includes a valve member movable within a valve body to contact a valve seat and block fluid communication between first and second passages. The valve seat and valve member each include a multi-layered coating having a harder metal nitride base layer and a softer metal nitride outer layer. The base layer is relatively incompliant to impacts between the valve member and the valve seat, and the outer layer is relatively compliant to the impacts and thereby deformable. Related methodology is disclosed.

主权项

1. A valve assembly for a fuel system in an internal combustion engine comprising:
a valve body having therein a valve seat located fluidly between a first fluid passage and a second fluid passage and being formed of a first metal substrate; a valve member movable within the valve body between a first position at which the valve member contacts the valve seat and blocks fluid communication between the first and second fluid passages, and a second position at which the fluid communication is open, and the valve member being formed of a second metal substrate; the valve seat and the valve member each including a multi-layer coating positioned within a sealing interface formed by the contact at the first position, and having a metal nitride base layer adherent to the corresponding first or second metal substrate, and a metal nitride outer layer; the metal nitride base layer having a first hardness, such that the metal nitride base layer is relatively incompliant to impacts between the valve member and the valve seat at the first position and limits wear of the valve member and the valve seat during service of the valve assembly in the fuel system; and the metal nitride outer layer having a second hardness, such that the metal nitride outer layer is relatively compliant to the impacts and is thereby deformable to enlarge the sealing interface during break-in of the valve assembly in the fuel system.