Abstract: In metal-on-metal sealing structures, the sealing criteria employed for high pressure liquid fuel does not work when sealing gaseous fuels. A technique for sealing a gaseous fuel between gaseous fuel conduits in an internal combustion engine includes forming a contact band between two surfaces of a sealing structure between a first conduit and a second conduit. A width of the contact band is at least equal to the larger of a minimum contact pressure width where contact pressure is at least equal to a predetermined minimum contact pressure; and a minimum yield zone width where at least one of the two surfaces have plastically deformed.

Abstract: A multi-fuel rail apparatus for an internal combustion engine communicates fuel from 10 a first fuel source and a second fuel source to a plurality of fuel injectors. Each fuel injector receives fuel from the multi-fuel rail apparatus through a branch connection for each fuel. The multi fuel rail apparatus has a first elongate member including a first longitudinal bore spaced apart from a second longitudinal bore and first and second fuel inlets for fluidly communicating first and second fuels into the first and 15 second longitudinal bores respectively. There is a branch connecting structure for each fuel injector along the first elongate member for fluidly connecting the first and second longitudinal bores with respective branch connections from respective fuel injectors.

Abstract: An improved body defining a restricted fluid flow passage in a fuel supply system for delivering a gaseous fuel to an internal combustion engine. The body is formed for installation between and fluidly connecting a gaseous fuel supply conduit and a gaseous fuel flow passage that defines a predetermined volume between the restricted fluid flow passage and a nozzle chamber of a fuel injector from which the gaseous fuel is injected into the internal combustion engine. The restricted fluid flow passage has the smallest effective flow area between the gaseous fuel supply conduit and the nozzle chamber. The restricted fluid flow passage is located a predetermined distance from an injection valve seal within the fuel injector. The predetermined distance is calculated as a function of the speed of sound in the gaseous fuel and an opened time of the fuel injector.

Abstract: A cycle-by-cycle skip-fire fuel-injection technique for pilot-ignited engines involve skip-firing selected combustion chambers when a low load condition is determined and modulating the fuel delivery to maintain the requisite engine power, while reducing pilot fuel quantity to a predetermined minimum. Overall pilot fuel consumption is thereby reduced.

Abstract: A multi-fuel rail apparatus for an internal combustion engine communicates fuel from 10 a first fuel source and a second fuel source to a plurality of fuel injectors. Each fuel injector receives fuel from the multi-fuel rail apparatus through a branch connection for each fuel. The multi fuel rail apparatus has a first elongate member including a first longitudinal bore spaced apart from a second longitudinal bore and first and second fuel inlets for fluidly communicating first and second fuels into the first and 15 second longitudinal bores respectively. There is a branch connecting structure for each fuel injector along the first elongate member for fluidly connecting the first and second longitudinal bores with respective branch connections from respective fuel injectors.

Abstract: An improved body defining a restricted fluid flow passage in a fuel supply system for delivering a gaseous fuel to an internal combustion engine. The body is formed for installation between and fluidly connecting a gaseous fuel supply conduit and a gaseous fuel flow passage that defines a predetermined volume between the restricted fluid flow passage and a nozzle chamber of a fuel injector from which the gaseous fuel is injected into the internal combustion engine. The restricted fluid flow passage has the smallest effective flow area between the gaseous fuel supply conduit and the nozzle chamber. The restricted fluid flow passage is located a predetermined distance from an injection valve seal within the fuel injector. The predetermined distance is calculated as a function of the speed of sound in the gaseous fuel and an opened time of the fuel injector.

Abstract: In metal-on-metal sealing structures, the sealing criteria employed for high pressure liquid fuel does not work when sealing gaseous fuels. An improved method for sealing a gaseous fuel between gaseous fuel conduits in an internal combustion engine comprises forming a contact band between two surfaces of a sealing structure between a first conduit and a second conduit. A width of the contact band is at least equal to the larger of a minimum contact pressure width where contact pressure is at least equal to a predetermined minimum contact pressure; and a minimum yield zone width where at least one of the two surfaces have plastically deformed.

Abstract: A method for correcting injection behavior of a fuel injector includes calculating a nominal value of a fuel injector family characteristic for an average fuel injector from a family of fuel injectors as a multi-variable function of engine operating conditions, calculating a corrected value of the fuel injector family characteristic as a function of the nominal value, and employing the corrected value when actuating the fuel injector to inject fuel.

Abstract: A method for controlling fuel pressure in an internal combustion engine consuming a gaseous fuel and a liquid fuel comprises steps of determining a gaseous fuel pressure target value as a function of an engine operating condition, pressurizing the liquid fuel to a liquid fuel pressure based on the gaseous fuel pressure target value, and regulating gaseous fuel pressure from the liquid fuel pressure. The gaseous fuel pressure equals the gaseous fuel pressure target value to within a predetermined range of tolerance. A corresponding system controls fuel pressure in a gaseous fuelled internal combustion engine.

Abstract: A method for controlling fuel pressure in an internal combustion engine consuming a gaseous fuel and a liquid fuel comprises steps of determining a gaseous fuel pressure target value as a function of an engine operating condition, pressurizing the liquid fuel to a liquid fuel pressure based on the gaseous fuel pressure target value, and regulating gaseous fuel pressure from the liquid fuel pressure. The gaseous fuel pressure equals the gaseous fuel pressure target value to within a predetermined range of tolerance. A corresponding apparatus controls fuel pressure in a gaseous fuelled internal combustion engine.

Abstract: A method for controlling fuel pressure in an internal combustion engine consuming a gaseous fuel and a liquid fuel comprises steps of determining a gaseous fuel pressure target value as a function of an engine operating condition, pressurizing the liquid fuel to a liquid fuel pressure based on the gaseous fuel pressure target value, and regulating gaseous fuel pressure from the liquid fuel pressure. The gaseous fuel pressure equals the gaseous fuel pressure target value to within a predetermined range of tolerance. A corresponding apparatus controls fuel pressure in a gaseous fuelled internal combustion engine.

Abstract: A method for controlling fuel pressure in an internal combustion engine consuming a gaseous fuel and a liquid fuel comprises steps of determining a gaseous fuel pressure target value as a function of an engine operating condition, pressurizing the liquid fuel to a liquid fuel pressure based on the gaseous fuel pressure target value, and regulating gaseous fuel pressure from the liquid fuel pressure. The gaseous fuel pressure equals the gaseous fuel pressure target value to within a predetermined range of tolerance. A corresponding system controls fuel pressure in a gaseous fuelled internal combustion engine.

Abstract: A cycle-by-cycle skip-fire fuel-injection technique for pilot-ignited engines involve skip-firing selected combustion chambers when a low load condition is determined and modulating the fuel delivery to maintain the requisite engine power, while reducing pilot fuel quantity to a predetermined minimum. Overall pilot fuel consumption is thereby reduced.

Abstract: A method for correcting injection behavior of a fuel injector includes calculating a nominal value of a fuel injector family characteristic for an average fuel injector from a family of fuel injectors as a multi-variable function of engine operating conditions, calculating a corrected value of the fuel injector family characteristic as a function of the nominal value, and employing the corrected value when actuating the fuel injector to inject fuel.

Abstract: A method for controlling fuel pressure in an internal combustion engine consuming a gaseous fuel and a liquid fuel comprises steps of determining a gaseous fuel pressure target value as a function of an engine operating condition, pressurizing the liquid fuel to a liquid fuel pressure based on the gaseous fuel pressure target value, and regulating gaseous fuel pressure from the liquid fuel pressure. The gaseous fuel pressure equals the gaseous fuel pressure target value to within a predetermined range of tolerance. A corresponding system controls fuel pressure in a gaseous fuelled internal combustion engine.

Abstract: A method for controlling fuel pressure in an internal combustion engine consuming a gaseous fuel and a liquid fuel comprises steps of determining a gaseous fuel pressure target value as a function of an engine operating condition, pressurizing the liquid fuel to a liquid fuel pressure based on the gaseous fuel pressure target value, and regulating gaseous fuel pressure from the liquid fuel pressure. The gaseous fuel pressure equals the gaseous fuel pressure target value to within a predetermined range of tolerance. A corresponding apparatus controls fuel pressure in a gaseous fuelled internal combustion engine.

Abstract: A dual fuel injection valve separately and independently injects two different fuels and comprises a dual needle assembly with a hollow open-ended outer needle and an inner needle disposed within the hollow interior. A cap cooperates with the outer needle to cover the open end, and the outer needle and the cap together comprise the inner valve body. The outer and inner needles are each movable independently from each other between respective open and closed positions. A spring disposed between the cap and the inner needle contributes to biasing the inner needle in the closed position. The cap can be joined to the outer needle, whereby the cap can provide a limit to the movement of the inner needle. In another embodiment the cap can be detached from the outer body, allowing the spring to space the cap away from the outer needle, assisting with biasing the outer needle closed.

Abstract: A dual fuel injection valve separately and independently injects two different fuels and comprises a dual needle assembly with a hollow open-ended outer needle and an inner needle disposed within the hollow interior. A cap cooperates with the outer needle to cover the open end, and the outer needle and the cap together comprise the inner valve body. The outer and inner needles are each movable independently from each other between respective open and closed positions. A spring disposed between the cap and the inner needle contributes to biasing the inner needle in the closed position. The cap can be joined to the outer needle, whereby the cap can provide a limit to the movement of the inner needle. In another embodiment the cap can be detached from the outer body, allowing the spring to space the cap away from the outer needle, assisting with biasing the outer needle closed.

Abstract: A dual fuel injection valve separately and independently injects two different fuels into a combustion chamber of an internal combustion engine. A first fuel is delivered to the injection valve at injection pressure and a second fuel is either raised to injection pressure by an intensifier provided within the injection valve, or delivered to the injection valve at injection pressure. Electronically controlled valves control hydraulic pressure in control chambers disposed within the injection valve. The pressure of the hydraulic fluid in these control chambers is employed to independently actuate a hollow outer needle that controls the injection of the first fuel. Disposed within the outer needle is an inner needle that controls the injection of the second fuel. The outer needle closes against a seat associated with the injection valve body and the inner needle closes against a seat associated with the outer needle.

Abstract: A gaseous and liquid fuel injection valve for an internal combustion engine comprises an injection valve body that houses two separate concentric fuel injection valve assemblies. The first valve assembly is a pilot fuel needle valve assembly, which comprises a first needle movable in the direction of the longitudinal axis of the body between an open and a closed position. The second valve assembly is a gaseous fuel needle valve assembly, which comprises a second needle movable in the direction of the longitudinal axis between an open and a closed position. The gaseous fuel needle valve assembly controls the injection of gaseous fuel into the combustion chamber through a plurality of gaseous fuel holes formed in a nozzle tip of the gaseous fuel needle valve assembly. At least one of the nozzle tips is rotatable to thereby change the position of the pilot fuel holes with respect to the gaseous fuel holes.