Enhanced needle motion controller

1. A controller for controlling a needle valve of a spring closing type fuel injector, comprising:

a fluid assist selectively exerting a force on the needle valve, the force acting in cooperation with a bias exerted by a return spring on the needle valve to effect a relatively low valve opening pressure of the needle valve and relatively very high valve closing pressure, said fluid assist being generated by a fluid under pressure acting on a pressure head surface having an area that is less than a needle valve opening surface, the needle valve opening surface being selectively communication with pressurized fuel.

2. The controller of claim 1 , the pressurized fuel generating a force on the needle valve opening surface in opposition to a force generated by the fluid under pressure acting on the pressure head surface.

3. The controller of claim 2 , the pressure head surface being translatably disposed in a pressure chamber, the pressure chamber being in fluid communication with a source of high pressure fluid.

4. The controller of claim 3 , the fluid communication with the source of high pressure fluid being effected via an orifice having a certain size.

5. The controller of claim 4 , the area of the orifice and the volume of the pressure chamber being cooperatively selected such that pressure in the pressure chamber builds at a lesser rate than pressure in a plunger chamber after initiation of an injection event.

6. The controller of claim 4 , the area of the orifice and the volume of the pressure chamber being cooperatively selected such that pressure in the pressure chamber decays at a lesser rate than pressure in a plunger chamber after termination of an injection event.

7. The controller of claim 1 , fluid in a pressure chamber acting to dampen opening translational motion of the needle valve.

8. The controller of claim 1 , fluid in a pressure chamber acting to effect in part a rapid closing translational motion of the needle valve.

9. The controller of claim 1 including a closing pin, the closing pin being translatable and having a bearing head being operably coupled to the needle valve and an opposed pressure head being acted on by the force exerted on the needle valve.

10. The controller of claim 9 including a biasing spring, the basing spring acting on the bearing head to cause the bearing head to be operably coupled to the needle valve.

11. A spring closing type fuel injector, comprising:

a controller for controlling a needle valve having a fluid assist selectively exerting a force on the needle valve, the force acting in cooperation with a bias exerted by a return spring on the needle valve to effect a relatively low valve opening pressure of the needle valve and relatively very high valve closing pressure, the fluid assist being generated by a fluid under pressure acting on a pressure head surface having an area that is that is less than a needle valve opening surface, the needle valve opening surface being selectively in communication with pressurized fuel.

12. The fuel injector of claim 11 , the pressurized fuel generating a force on the needle valve opening surface in opposition to a force generated by the fluid under pressure acting on the pressure head surface.

13. The fuel injector of claim 12 , the pressure head surface being translatably disposed in a pressure chamber, the pressure chamber being in fluid communication wit a source of high pressure fluid.

14. The fuel injector of claim 13 , the fluid communication with the source of high pressure fluid being effected via an orifice having a certain size.

15. The fuel injector of claim 14 , the area of the orifice and the volume of the pressure chamber being cooperatively selected such that pressure in the pressure chamber builds at a lesser rate than pressure in a plunger chamber after initiation of an injection event.

16. The fuel injector of claim 14 , the area of the orifice and the volume of the pressure chamber being cooperatively selected such that pressure in the pressure chamber decays at a lesser rate than pressure in a plunger chamber after termination of an injection event.

17. The fuel injector of claim 11 , fluid in a pressure chamber acting to dampen opening translational motion of the needle valve.

18. The fuel injector of claim 11 , fluid in a pressure chamber acting to effect in part a rapid closing translational motion of the needle valve.

19. The fuel injector of claim 11 including a closing pin, the closing pin being translatable and having a bearing bead being operably coupled to the needle valve and an opposed pressure head being acted on the force exerted on the needle valve.

20. The fuel injector of claim 19 including a biasing spring, the basing spring acting on the bearing head to cause the bearing head to be operably coupled to the needle valve.

21. A method for controlling a needle valve of a spring closing type fuel injector, comprising:

selectively exerting a force on the needle valve by means of a fluid assist, the force acting in cooperation wit a bias exerted by a return spring on the needle valve to effect a relatively low valve opening pressure of the needle valve and relatively very high valve closing pressure, and generating the fluid assist by a fluid under pressure acting on a pressure head surface having an area that is that is less than a needle valve opening surface, the needle valve opening surface being selectively in communication with pressurized fuel.

22. The method of claim 21 , including generating the force by means of pressurized fuel acting on the needle valve opening surface in opposition to a force generated by the fluid under pressure acting on the pressure head surface.

23. The method of claim 22 , including translatably disposing the pressure head surface in a pressure chamber, the pressure chamber being in fluid communication with a source of high pressure fluid.

24. The method of claim 23 , including effecting the fluid communication with the source of high pressure fluid via an orifice having a certain size.

25. The method of claim 24 , including cooperatively selecting the area of the orifice and the volume of the pressure chamber such that pressure in the pressure chamber builds at a lesser rate than pressure in a plunger chamber after initiation of an injection event.

26. The method of claim 24 , including cooperatively selecting the area of the orifice and the volume of the pressure chamber such that pressure in the pressure chamber decays at a lesser rate than pressure in a plunger chamber after termination of an injection event.

27. The method of claim 21 , including dampening opening translational motion of the needle valve by means of a fluid in a pressure chamber.

28. The method of claim 21 , including effecting in part a rapid closing translational motion of the needle valve by means of a fluid in a pressure chamber.

29. The method of claim 21 including translatably disposing a closing pin in a connector, operably coupling a closing pin being bearing head being to the needle valve and acting on an opposed pressure head being by the force exerted on the needle valve.

30. The method of claim 29 including acting on the bearing head to cause the bearing head to be operably coupled to the needle valve by means of a biasing spring.