Twin outlet check liquid fuel injector for dual fuel system

A fuel system for an internal combustion engine comprising:

• a pressurized liquid fuel supply;
• a plurality of liquid fuel injectors each defining a high pressure inlet passage, a first set of nozzle outlets, a second set of nozzle outlets, a first control chamber and a second control chamber each in fluid communication with the high pressure inlet passage, and a low pressure space;
• the plurality of liquid fuel injectors each including a first outlet check having a closing hydraulic surface exposed to a fluid pressure of the first control chamber, and a second outlet check having a closing hydraulic surface exposed to a fluid pressure of the second control chamber;
• the plurality of liquid fuel injectors each further including a first injection control valve positioned fluidly between the first control chamber and the low pressure space, and a second injection control valve positioned fluidly between the second control chamber and the low pressure space;
• the plurality of liquid fuel injectors each further defining a first set of orifices arranged in an A-F-Z pattern among the high pressure inlet passage, the low pressure space, and the first control chamber, and a second set of orifices arranged in an A-F-Z pattern among the high pressure inlet passage, the low pressure space, and the second control chamber;
• the plurality of liquid fuel injectors each further defining a common nozzle supply cavity in fluid communication with the high pressure inlet passage, and the first outlet check and the second outlet check each being movable between an open position where the corresponding first set of nozzle outlets and second set of nozzle outlets are in fluid communication with the common nozzle supply cavity, and a closed position;
• a pressurized gaseous fuel supply, and at least one gaseous fuel admission valve that is separate from the plurality of liquid fuel injectors;
• each of the plurality of liquid fuel injectors further includes a stack having an orifice plate with an upper plate side, and a lower plate side exposed to the first control chamber, the second control chamber, and the common nozzle supply cavity.

An orifice plate for a stack in a liquid fuel injector in a fuel system comprising:

• a one-piece orifice plate body defining a center axis extending between an upper plate body side and a lower plate body side, and an outer peripheral edge extending circumferentially around the center axis;
• the orifice plate body further having a plurality of raised sealing surfaces formed on the upper side, for forming seals with an adjacent stack piece in the stack, and a recessed surface positioned axially inward of the raised sealing surfaces;
• the orifice plate body further having a first inlet passage and a second inlet passage extending between the upper plate body side and the lower plate body side, for feeding high pressure fuel to a first control chamber for a first outlet check and a second control chamber for a second outlet check, respectively;
• the orifice plate body further having a first outlet passage and a second outlet passage extending between the lower plate body side and the upper plate body side for connecting the first and the second control chamber to a low pressure space;
• a first set of orifices in the orifice plate body including a first A-orifice formed in the first outlet passage, a first Z-orifice formed in the first inlet passage, and a first F-orifice;
• a second set of orifices in the orifice plate body and including a second A-orifice formed in the second outlet passage, a second Z-orifice formed in the second inlet passage, and a second F-orifice;
• the first and the second F-orifices fluidly connecting the first and the second outlet passages to the lower plate body side to fluidly connect a nozzle supply cavity in the liquid fuel injector to each of the first and the second control chambers by way of the first and the second outlet passages;
• a first connector channel is formed in the upper plate body side and fluidly connects the first inlet passage to the second inlet passage;
• a second connector channel is formed in the upper plate body side and fluidly connects the first outlet passage to the first F-orifice;
• and
• a third connector channel is formed in the upper plate body side and fluidly connects the second outlet passage to the second F-orifice.