Fuel injector with at least one movable needle-guide

A fuel injector of the type used to inject fuel into a cylinder of an internal combustion engine when installed therein, the engine having a high-pressure fuel supply which delivers fuel to said injector and a low-pressure fuel return which removes fuel from said injector, said injector comprising:

• an injector body which defines an axis, an interior cavity and an apertured nozzle region fluidly connected with the engine cylinder when said injector is installed in the engine;
• a needle valve assembly at least partially disposed within said interior cavity for movement between first and second positions, said needle blocking fuel flow through said nozzle region when said needle is in said first position and said needle permitting fuel flow through said nozzle region when said needle is in said second position;
• at least one movable needle-guide comprised of a plurality of discrete members disposed between said needle and said injector body, said discrete members permitting only substantially axial movement of said needle;
• and
• wherein said injector body and said needle valve assembly are electrically-conductive;
• and
• said discrete members are electrically-insulating.

A fuel injector of the type used to inject fuel into a cylinder of an internal combustion engine when installed therein, the engine having a high-pressure fuel supply which delivers fuel to said injector and a low-pressure fuel return which removes fuel from said injector, said injector comprising:

• an injector body which defines an axis, an interior cavity and an apertured nozzle region fluidly connected with the engine cylinder when said injector is installed in the engine;
• a needle valve assembly at least partially disposed within said interior cavity for movement between first and second positions, said needle blocking fuel flow through said nozzle region when said needle is in said first position and said needle permitting fuel flow through said nozzle region when said needle is in said second position;
• at least one movable needle-guide comprised of a plurality of discrete members disposed between said needle and said injector body, said discrete members permitting only substantially axial movement of said needle;
• and
• wherein said discrete members are spherical and are at least partially comprised of a material selected from the group consisting of ceramics, diamond-like carbon and aluminum oxide.

A fuel injector of the type used to inject fuel into a cylinder of an internal combustion engine when installed therein, said injector comprising:

• an injector body which defines an axis, an interior cavity and an apertured nozzle region fluidly connected between the high-pressure fuel supply and the engine cylinder when said injector is installed in the engine;
• a needle valve assembly at least partially disposed within said injector for reciprocal movement along said axis between a first and second position wherein said needle blocks fuel flow into the engine cylinder and a second position wherein said needle does not block fuel flow into the engine cylinder;
• and
• means for electrically isolating said needle from said body when said needle is in said second position.