A fuel injector for an engine includes a connection to a fuel source, a nozzle which provides an outlet from the fuel injector, a fuel path from the fuel source to the nozzle, a valve between the fuel path and the nozzle, and a gas injection mechanism configured to insert a gas core into the fuel.

A fuel injector for an engine includes a connection to a fuel source, a nozzle which provides an outlet from the fuel injector, a fuel path from the fuel source to the nozzle, a valve between the fuel path and the nozzle, and a gas injection mechanism configured to insert a gas core into the fuel.

A large two-stroke turbocharged compression-ignited internal combustion crosshead engine with a plurality of cylinders has at least one pressure booster for each cylinder for boosting fuel pressure, two or more electronically controlled fuel valves for each cylinder with an inlet of the two or more electronically controlled fuel valves being connected to an outlet of the at least one pressure booster. An electronic control unit is connected to the at least one pressure booster and the two or more electronically controlled fuel valves. The electronic control unit is configured to determine a start time for a fuel injection event, activate the at least one pressure booster ahead of the determined start time and pen the two or more electronically controlled fuel valves at the determined start time.

A large two-stroke turbocharged compression-ignited internal combustion crosshead engine with a plurality of cylinders has at least one pressure booster for each cylinder for boosting fuel pressure, two or more electronically controlled fuel valves for each cylinder with an inlet of the two or more electronically controlled fuel valves being connected to an outlet of the at least one pressure booster. An electronic control unit is connected to the at least one pressure booster and the two or more electronically controlled fuel valves. The electronic control unit is configured to determine a start time for a fuel injection event, activate the at least one pressure booster ahead of the determined start time and pen the two or more electronically controlled fuel valves at the determined start time.

An internal combustion engine has fuel injectors for a first fuel and separate fuel injector-igniters for a second fuel. The first fuel may be a compression-ignition fuel such as diesel fuel while the second fuel is a lower cetane fuel that requires external energy for controlled ignition. For example, the second fuel may be natural gas. Such engines have applications in a wide range of fields, particularly those fields requiring large-displacement slow- and medium-speed engines. Such engines are particularly well adapted for use in railway locomotives. A locomotive equipped with such an engine may operate primarily on natural gas, and thereby take advantage of the significant price difference between natural gas and diesel fuel, while permitting switch over to operation on 100% diesel fuel.

An internal combustion engine has fuel injectors for a first fuel and separate fuel injector-igniters for a second fuel. The first fuel may be a compression-ignition fuel such as diesel fuel while the second fuel is a lower cetane fuel that requires external energy for controlled ignition. For example, the second fuel may be natural gas. Such engines have applications in a wide range of fields, particularly those fields requiring large-displacement slow- and medium-speed engines. Such engines are particularly well adapted for use in railway locomotives. A locomotive equipped with such an engine may operate primarily on natural gas, and thereby take advantage of the significant price difference between natural gas and diesel fuel, while permitting switch over to operation on 100% diesel fuel.

A dual-fuel fuel injector, having: a first nozzle needle for discharge of liquid fuel via a first nozzle arrangement; and a multiplicity of second nozzle needles, arranged around the first nozzle needle and controlled in terms of axial stroke, for discharge of gaseous fuel via a second nozzle arrangement. Each of the second nozzle needles has for controlling the stroke thereof, a respective control chamber in the injector which can be charged with and relieved of pressure by a control fluid. The dual-fuel fuel injector has an annular duct which can be charged with and relieved of pressure by the control fluid. The dual-fuel fuel injector is designed such that, for controlling the stroke of the second nozzle needles, the control chambers for the second nozzle needles are charged with and relieved of pressure by the control fluid proceeding from the annular duct.

A dual-fuel fuel injector, having: a first nozzle needle for discharge of liquid fuel via a first nozzle arrangement; and a multiplicity of second nozzle needles, arranged around the first nozzle needle and controlled in terms of axial stroke, for discharge of gaseous fuel via a second nozzle arrangement. Each of the second nozzle needles has for controlling the stroke thereof, a respective control chamber in the injector which can be charged with and relieved of pressure by a control fluid. The dual-fuel fuel injector has an annular duct which can be charged with and relieved of pressure by the control fluid. The dual-fuel fuel injector is designed such that, for controlling the stroke of the second nozzle needles, the control chambers for the second nozzle needles are charged with and relieved of pressure by the control fluid proceeding from the annular duct.

A fuel valve includes a housing, a nozzle with nozzle holes opening to a volume inside the nozzle at the front end of the housing, a gaseous fuel inlet port in the housing connected to high pressure gaseous fuel, an axially displaceable valve needle received in a longitudinal bore in the housing, and rests on a valve seat in a closed position and has lift from the valve seat in an open position, the valve seat placed between a fuel chamber and an outlet port, the fuel chamber connected to the fuel inlet port, the outlet port connected to the volume in the nozzle, an actuator system for moving the needle between the closed and open positions, an ignition liquid inlet port connected to high pressure ignition liquid, and conduit connecting the ignition liquid inlet port to the fuel chamber, the conduit including a fixed flow restriction.

A fuel valve includes a housing, a nozzle with nozzle holes opening to a volume inside the nozzle at the front end of the housing, a gaseous fuel inlet port in the housing connected to high pressure gaseous fuel, an axially displaceable valve needle received in a longitudinal bore in the housing, and rests on a valve seat in a closed position and has lift from the valve seat in an open position, the valve seat placed between a fuel chamber and an outlet port, the fuel chamber connected to the fuel inlet port, the outlet port connected to the volume in the nozzle, an actuator system for moving the needle between the closed and open positions, an ignition liquid inlet port connected to high pressure ignition liquid, and conduit connecting the ignition liquid inlet port to the fuel chamber, the conduit including a fixed flow restriction.