Fuel injection nozzle head offers seating face for needle valve seat where downstream shutter stabilizes fuel flow section upstream of port at all needle lift values.

摘要

The seat on the head of the needle valve (3) homes onto the valve seat (8) of the nozzle (2) to block the fluid link between fuel channel (5) and discharge port (7) and so halt the fuel spray. The needle valve is raised to maximum lift within the low-lift range when the fuel pressure on the pressure excitation area (12) rises to a first opening pressure, and then to a second maximum within the high-lift range when fuel pressure exceeds a second opening pressure. A shutter (17) in the fuel channel downstream of the seating area (8) but upstream of the discharge port entry when the needle valve is in the low-lift range, has a flow section traveled by the fuel flow. This area is held constantly in the low-lift range and gives its minimum channel (5) flow section when the needle valve is in its first maximum lift setting.