Fuel admission mixer for fumigated engine system

A fuel admission mixer for a gaseous fuel engine system comprising:

• a mounting flange portion forming a fuel inlet;
• a fuel tube extending from the mounting flange portion, and including a tube wall having an inner tube surface, and an outer tube surface;
• the inner tube surface extending circumferentially around a feed passage center axis, and forming a feed passage for feeding gaseous fuel from the fuel inlet to the distal fuel outlet;
• the tube wall includes a back wall portion extending part-circumferentially around the feed passage center axis, and a front wall portion extending part-circumferentially around the feed passage center axis;
• and
• the front wall portion is slotted and forms a plurality of mixing air admission slots extending from the outer tube surface to the inner tube surface, for admitting mixing air into the feed passage, each elongated in a circumferential direction, and the back wall portion is unslotted.

A method of operating an engine system comprising:

• admitting a gaseous fuel via fumigation into a fuel admission mixer fluidly connected to an intake conduit extending to an engine;
• ramming mixing air into a feed passage of the fuel admission mixer through a plurality of mixing air admission slots in the fuel admission mixer;
• producing vortices of the mixing air and gaseous fuel based on the ramming of the mixing air;
• and
• conveying the mixing air and gaseous fuel into the intake conduit for combustion in the engine.