In-cylinder dynamic gas blending fuel injector and dual fuel engine

摘要

A dual fuel engine utilizes a compression ignited pilot injection of liquid diesel fuel to ignite a mixture of gaseous fuel and air in each engine cylinder. The gaseous fuel is injected at a relatively low pressure directly into the engine cylinder from a fuel injector. The liquid diesel fuel is injected directly into the engine cylinder from the same fuel injector. In-cylinder dynamic gas blending during the compression stroke can reduce potential hydrocarbon slip that could occur when unburned fuel resides in crevice volumes within the engine cylinder.

主权项

1. A fuel injector comprising:
an injector body that defines a liquid fuel inlet, a gaseous fuel inlet, a liquid nozzle outlet set, a gaseous nozzle outlet set and a drain outlet; a first electrical actuator, a second electrical actuator, a liquid nozzle chamber, a gaseous nozzle chamber, a first needle control chamber and a second needle control chamber disposed in the injector body; the liquid nozzle chamber, the first needle control chamber and the second needle control chamber being fluidly connected to the liquid fuel inlet; the gaseous nozzle chamber being fluidly connected to the gaseous fuel inlet a first control valve member operably coupled to the first electrical actuator and being movable between a first position that blocks the first needle control chamber to the drain outlet, and a second position that fluidly connects the first needle control chamber to the drain outlet; a second control valve member operably coupled to the second electrical actuator and being movable between a first position that blocks the second needle control chamber to the drain outlet, and a second position that fluidly connects the second needle control chamber to the drain outlet; a liquid needle valve member with an opening hydraulic surface exposed to fluid pressure in the liquid nozzle chamber, and a closing hydraulic surface exposed to fluid pressure in the first needle control chamber, and being movable between a closed position blocking the liquid nozzle chamber to the liquid nozzle outlet set, and an open position fluidly connecting the liquid nozzle chamber to the liquid nozzle outlet set; a gaseous needle valve member with an opening hydraulic surface exposed to fluid pressure in the liquid nozzle chamber, and a closing hydraulic surface exposed to fluid pressure in the second needle control chamber, and being movable between a closed position blocking the gaseous nozzle chamber to the gaseous nozzle outlet set, and an open position fluidly connecting the gaseous nozzle chamber to the gaseous nozzle outlet set; a drain annulus surrounding the gaseous needle valve member and being fluidly connected to the drain outlet.