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

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.

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.

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.