Patent ID: 6851630

Claim:
An electromagnetic fuel injection valve comprising: a valve seat member having a valve seat at one end; a valve housing coupled at one end thereof to the other end of said valve seat member; a stationary core coupled to the other end of said valve housing; and a valve assembly comprising: a movable core slidably accommodated in said valve housing so that said movable core is opposed to said stationary core, and a valve member connected to said movable core through a rod portion and adapted to cooperate with said valve seat, said valve housing being provided with a guide portion on which said valve assembly is axially slidably carried, said guide portion being disposed directly between a lowermost end of said stationary core and an uppermost end of said valve housing, said valve assembly having a high-hardness coating formed on an outer peripheral surface contacting with said guide portion, wherein said high-hardness coating is formed by depositing diamond-like carbon on the outer peripheral surface of said valve assembly by ion plating using an organic gas as a starting material, the surface roughness Rmax of said high-hardness coating being set in a range of 0.05 to 0.2 μm.