Apparatus and method for igniting a gaseous fuel in a direct injection internal combustion engine

1. A method of igniting gaseous fuel directly introduced into a combustion chamber of an internal combustion engine comprising steps of:

heating a space around a fuel injector nozzle;

introducing a pilot amount of gaseous fuel through a pilot injection passageway in a fuel injector nozzle into said combustion chamber;

igniting said pilot amount of gaseous fuel;

introducing a main amount of gaseous fuel through a main injection passageway in said fuel injector nozzle into said combustion chamber;

using heat from combustion of said pilot amount of gaseous fuel to ignite said main amount of gaseous fuel; and

controlling gaseous fuel flow into said combustion chamber between said main amount of gaseous fuel and said pilot amount of gaseous fuel by providing a ratio between a main cross-sectional area of said main injection passageway and a pilot cross-sectional area of said pilot injection passageway within a range of 4 to 49.

2. The method of claim 1 , wherein said gaseous fuel is natural gas.

3. The method of claim 1 , wherein said gaseous fuel is selected from the group consisting of methane, propane, ethane, biogas, landfill gas, hydrogen and mixtures of these fuels.

4. The method of claim 1 , further comprising absorbing heat around said fuel injector nozzle to assist with combustion of said pilot amount and said main amount.

5. The method of claim 1 , wherein said igniting said pilot amount is by one of:

heating a space around said fuel injector nozzle wherein said pilot amount auto-ignites; and

spark igniting said pilot amount.

6. The method of claim 1 , wherein said pilot amount is within a range of 2% to 20% of total gaseous fuel introduced.

7. The method of claim 1 , wherein said pilot amount is within a range of 2% to 10% of total gaseous fuel introduced.

8. The method of claim 1 , wherein said pilot amount is within a range of 2% to 8% of total gaseous fuel introduced.

9. The method of claim 1 , wherein said pilot amount is introduced during a first stage injection event before said main amount is introduced.

10. The method of claim 9 , wherein said main amount is introduced in a second stage injection event after said pilot amount ignites.

11. The method of claim 9 , further comprising:

introducing a second pilot amount of said gaseous fuel before said first stage injection event; and

igniting said second pilot amount with an external ignition source whereby combustion of said second pilot amount heats said combustion chamber.

12. The method of claim 11 , wherein said external ignition source is a spark.

13. The method of claim 1 , further comprising impacting a pilot fuel jet emanating from said pilot injection passageway into said combustion chamber against a diverting and retaining member wherein said pilot amount is diverted around said fuel injector nozzle.

14. The method of claim 1 , further comprising co-injecting a second fuel such that ignitability of said gaseous fuel is improved.

15. The method of claim 14 , wherein said second fuel is introduced into said combustion chamber separately from said gaseous fuel.

16. The method of claim 14 , wherein said second fuel forms a mixture with said gaseous fuel, and said mixture is introduced into said combustion chamber.

17. The method of claim 1 , wherein said ratio is within a range of 9 to 49.

18. The method of claim 1 , wherein said ratio is within a range of 11.5 to 49.

19. A method of igniting gaseous fuel directly introduced into a combustion chamber of an internal combustion engine comprising steps of:

heating a space around a fuel injector nozzle;

introducing a main amount of gaseous fuel through a main injection passageway in a first fuel injector nozzle into said combustion chamber;

introducing a pilot amount of gaseous fuel through a pilot injection passageway in a second fuel injector nozzle into said combustion chamber;

igniting said pilot amount of gaseous fuel;

using heat from combustion of said pilot amount of gaseous fuel to ignite said main amount of gaseous fuel; and

controlling gaseous fuel flow into said combustion chamber between said main amount of gaseous fuel and said pilot amount of gaseous fuel by providing a ratio between a main cross-sectional area of said main injection passageway and a pilot cross-sectional area of said pilot injection passageway within a range of 4 to 49.

20. The method of claim 19 , wherein said main amount is introduced into an intake manifold upstream from an intake valve of said combustion chamber.

21. The method of claim 19 , wherein said ratio is within a range of 9 to 49.

22. The method of claim 19 , wherein said ratio is within a range of 11.5 to 49.

23. An apparatus for igniting gaseous fuel in a combustion chamber of an internal combustion engine comprising:

a fuel injector for directly introducing gaseous fuel into said combustion chamber; said fuel injector comprising a nozzle and having a pilot injection passageway and a main injection passageway, said pilot injection passageway comprising a pilot cross-sectional area perpendicular to gaseous fuel flow therethrough, and said main injection passageway comprising a main cross-sectional area perpendicular to gaseous fuel flow therethrough, a ratio of said main cross-sectional area to said pilot cross-sectional area is within a range of 4 to 49;

an ignition source comprising a heated surface extending annularly around the nozzle of the fuel injector;

a controller operatively connected with said fuel injector and said ignition source and configured to:

actuate said fuel injector to introduce a pilot amount of gaseous fuel through said pilot injection passageway forming a pilot jet;

actuate said ignition source to ignite said pilot jet; and

actuate said fuel injector to introduce a main amount of gaseous fuel through said main injection passageway forming a main jet wherein said main jet ignites due to heat from combustion of said pilot jet.

24. The apparatus of claim 23 , wherein the gaseous fuel is natural gas.

25. The apparatus of claim 23 , wherein said gaseous fuel is selected from the group consisting of methane, propane, ethane, biogas, landfill gas, hydrogen and mixtures of these fuels.

26. The apparatus of claim 23 , wherein said ratio is within a range of 9 to 49.

27. The apparatus of claim 23 , wherein said ratio is within a range of 11.5 to 49.

28. The apparatus of claim 23 , wherein said ignition source comprises a sparking mechanism.

29. The apparatus of claim 23 , wherein said ignition source comprises a heating coil.

30. The apparatus of claim 23 , wherein said ignition source comprises an induction heater.

31. The apparatus of claim 23 , wherein said pilot amount is introduced during a first stage injection event and said main amount is introduced during a second stage injection event, and said controller is further configured to:

actuate said fuel injector to introduce a second pilot amount of gaseous fuel through said pilot injection passageway before said first stage injection event; and

actuate a sparking mechanism to spark ignite said second pilot amount of said gaseous fuel;

wherein heat from combustion of said second pilot amount assists with ignition of said pilot amount.

32. The apparatus of claim 23 , further comprising a diverting and retaining member operable to divert flow of said pilot jet around said fuel injector.

33. The apparatus of claim 23 , further comprising a second fuel injector for introducing a second fuel directly into said combustion chamber, said controller further configured to actuate said second fuel injector.

34. The apparatus of claim 33 , wherein said second fuel is selected from the group consisting of hydrogen and diesel.

35. The apparatus of claim 23 , further comprising a heat absorbent layer extending annularly around said fuel injector.

36. An apparatus for igniting a gaseous fuel in a combustion chamber of an internal combustion engine comprising:

a first fuel injector for directly introducing said gaseous fuel into said combustion chamber, said first fuel injector comprising a pilot injection passageway, said pilot injection passageway comprising a pilot cross-sectional area perpendicular to gaseous fuel flow therethrough;

an intake valve upstream from said combustion chamber;

a second fuel injector for introducing said gaseous fuel upstream from said intake valve and comprising a main injection passageway, said main injection passageway comprising a main cross-sectional area perpendicular to gaseous fuel flow therethrough, a ratio of said main cross-sectional area to said pilot cross-sectional area is within a range of 4 to 49;

an ignition source;

a controller operatively connected with said first and second fuel injectors and configured to:

actuate said second fuel injector to introduce a main amount of said gaseous fuel whereby said main amount forms a premixed mixture in said combustion chamber; and

actuate said first fuel injector to introduce a pilot amount of said gaseous fuel through said pilot injection passageway.

37. The apparatus of claim 36 , wherein said ratio is within a range of 9 to 49.

38. The apparatus of claim 36 , wherein said ratio is within a range of 11.5 to 49.

39. The apparatus of claim 36 , wherein said ignition source comprises a sparking mechanism.

40. The apparatus of claim 36 , wherein said ignition source comprises a heating coil.

41. The apparatus of claim 36 , wherein said ignition source comprises an induction heater.

42. The apparatus of claim 36 , further comprising a heat absorbent layer extending annularly around said first fuel injector.