Injection nozzle
View Patent ↗An injection nozzle comprising a nozzle body provided with a bore within which a valve needle is moveable, the valve needle being engageable with a valve seating to control fuel delivery through a set of nozzle outlets, said nozzle outlets including respective entry openings defined in a wall of a sac volume of the nozzle body, wherein the valve needle includes a first valve region, a second valve region and a seat region defined by a transition between the first and second valve regions which seats against the valve seating when the nozzle is in a non-injecting state. The valve needle comprises a third valve region adjacent the second valve region, the third valve region having an outer surface defining a curved profile, the end of the outer surface terminating substantially in alignment with the entry openings when the valve needle is engaged with the valve seating.
1. An injection nozzle for an internal combustion engine, the injection nozzle comprising:
a nozzle body provided with a bore within which a valve needle is moveable along an axis,
the valve needle being engageable with a valve seating to control fuel delivery through a set of nozzle outlets,
wherein the valve seating transitions into a sac volume of the nozzle body defined by a steeply walled portion located at the very bottom of the bore,
said nozzle outlets including respective entry openings defined in a wall of the sac volume,
wherein the valve needle includes a first valve region, a second valve region and a seat region defined by a transition between the first and second valve regions and which seats against the valve seating when the nozzle is in a non-injecting state,
the valve needle comprising a third valve region, adjacent the second valve region, the third valve region having an outer surface defining a curved profile, the end of the outer surface terminating in alignment with a plane passing through the centers of the entry openings, said plane being perpendicular to the axis, when the valve needle is engaged with the valve seating, wherein the outer surface ( 65 ) of the third valve region is spaced a distance (L) from the entry openings of the nozzle outlets of between 10% and 30% of the entry diameter (D) of the sac volume.
2. The injection nozzle of claim 1 , wherein the first valve region and the second valve region are frustoconical in form and are adjacent to one another so as to define a seating line at their mutual boundary.
3. The injection nozzle of claim 1 , wherein the third valve region is a neiloidic frustum.
4. The injection nozzle of claim 1 , wherein the third valve region adjoins the second valve region at a relative downstream position.
5. The injection nozzle of claim 1 , where the predetermined distance (L) is between 15% and 25% of the entry diameter (D) of the sac volume.
6. The injection nozzle of claim 5 , where the predetermined distance (L) is between 17% and 23% of the entry diameter (D) of the sac volume.
7. The injection nozzle of claim 6 , where the predetermined distance (L) is approximately 20% of the entry diameter (D) of the sac volume.
8. The injection nozzle of claim 1 , wherein a peripheral edge of the third valve region is chamfered or radiussed.
9. The injection nozzle of claim 1 , wherein the valve seating is conical and defines a seat cone angle of between 60 degrees and 140 degrees.
10. The injection nozzle of claim 9 , wherein the conical valve seating defines a seat cone angle of between 90 degrees and 140 degrees.
11. The injection nozzle of claim 10 , wherein the conical valve seating defines a seat cone angle of 120 degrees.
12. The injection nozzle of claim 1 , wherein the distance between the seating region and the nozzle outlet entry holes is between approximately 20% and 60% of a seating diameter of the nozzle.
13. The injection nozzle of claim 12 , wherein the distance between the seating region and the nozzle outlet entry holes is between approximately 30% and 50% of a seating diameter of the nozzle.
14. An injection nozzle for an internal combustion engine, the injection nozzle comprising:
a nozzle body provided with a bore within which a valve needle is moveable along an axis,
the valve needle being engageable with a valve seating to control fuel delivery through a set of nozzle outlets,
wherein the valve seating transitions into a sac volume of the nozzle body defined by a steeply walled portion located at the very bottom of the bore,
said nozzle outlets including respective entry openings defined in a wall of the sac volume,
wherein the valve needle includes a first valve region, a second valve region and a seat region defined by a transition between the first and second valve regions and which seats against the valve seating when the nozzle is in a non-injecting state,
the valve needle comprising a third valve region, adjacent the second valve region, the third valve region having an outer surface defining a curved profile, the end of the outer surface terminating in alignment with a plane passing through the centers of the entry openings, said plane being perpendicular to the axis, when the valve needle is engaged with the valve seating, wherein the outer surface of the third valve region is spaced a distance (L) from the entry openings of the nozzle outlets of between 10% and 30% of the entry diameter (D) of the sac volume.