Ignition charge formation stabilization in gaseous fuel engine system

A method of stabilizing ignition charge formation in a gaseous fuel engine system comprising:

• producing a flame kernel within a pocket in an igniter in a gaseous fuel engine via a spark;
• shielding the pocket from a flow of gases in a cylinder fluidly connected to the pocket to inhibit extinguishment of the flame kernel;
• igniting an ignition charge containing gaseous molecular hydrogen fuel and air within the pocket via the flame kernel;
• forming the ignition charge from a mixture of gaseous molecular hydrogen fuel and air conveyed into the pocket and having a substitution ratio of at least 10%;
• exchanging gases between the pocket and the cylinder in advance of producing the flame kernel to clear the pocket of residual combustion gases;
• and
• limiting combustion phasing errors in the gaseous fuel engine system based on the exchanging gases between the pocket and the cylinder;
• and
• opening a gaseous fuel admission valve to convey the gaseous molecular hydrogen fuel for forming the ignition charge into the cylinder from a hydrogen fuel supply.

A gaseous fuel engine system comprising:

• an engine housing having a cylinder formed therein;
• a piston reciprocable in the cylinder between a top-dead-center position and a bottom-dead-center position;
• a gaseous molecular hydrogen fuel supply;
• an intake system connecting between the gaseous molecular hydrogen fuel supply and the cylinder;
• an igniter having a pocket formed therein, spark electrodes forming a spark gap within the pocket, and a shielding wall;
• the shielding wall extending around the pocket and shielding the pocket from gas flow in the cylinder sufficiently to establish within the pocket a flow field for protecting a flame kernel produced by energizing the spark electrodes from extinguishment;
• and
• the shielding wall further having formed therein at least one opening sized sufficiently to clear the pocket of residual combustion gases in advance of forming an ignition charge within the pocket containing the gaseous molecular hydrogen fuel and air.