A FUEL VALVE FOR PILOT OIL INJECTION AND FOR INJECTING GASEOUS FUEL INTO THE COMBUSTION CHAMBER OF A LARGE TWO-STROKE SELF-IGNITING INTERNAL COMBUSTION ENGINE

摘要

A fuel valve (50) for pilot oil injection and for injecting gaseous fuel into the combustion chamber of a self-igniting internal combustion engine. The fuel valve comprises an elongated fuel valve housing (52) with a rear end and a front end, a nozzle (54) with nozzle holes (56), a gaseous fuel inlet port (53) for connection to a source (60) of pressurized gaseous fuel and an axially displaceable valve needle (61) having a closed position and an open position and resting on a seat (69) in the closed position and thus preventing flow from the gaseous fuel inlet port (53) to the nozzle (54). In the open position the axially displaceable needle (61) has lift from the seat (69) thereby allowing flow from the gaseous fuel inlet port (53) to the nozzle (54). The fuel valve further comprises an actuator system for controllably moving the axially displaceable valve needle (61) between the closed position and the open position, a pilot oil port (78) for connection to a source of pilot oil, a pilot oil injection conduit (67) extending axially inside the axially displaceable needle (61) and a pump chamber (80) with an inlet fluidly connected to the pilot oil port (78) and an outlet connected to a first end of the pilot oil supply conduit (67). The pump chamber (80) contracts when the axially displaceable needle (61) is moved from the closed position to the open position and the pump chamber (80) expands when the axially displaceable needle (61) is moved from the open position to the closed position. A second end of the pilot oil injection conduit (67) is fluidly connected to the nozzle (54) so that pilot oil is delivered to the nozzle (54) when the pump chamber (80) contracts.