A fuel injector includes a nozzle body, and spray ducts coupled to the nozzle body and in spray path alignment with spray orifices therein. A nozzle check is movable within the nozzle body to open and close the spray orifices. Each of the spray ducts defines a duct center axis, and includes a center body forming, together with a duct inner surface, a spray jet passage circumferential of the duct center axis and reduced in area in a direction of spray jet advancement from the nozzle body.

A fuel injector includes a nozzle body, and spray ducts coupled to the nozzle body and in spray path alignment with spray orifices therein. A nozzle check is movable within the nozzle body to open and close the spray orifices. Each of the spray ducts defines a duct center axis, and includes a center body forming, together with a duct inner surface, a spray jet passage circumferential of the duct center axis and reduced in area in a direction of spray jet advancement from the nozzle body.

A dual-fluid injection system for an internal combustion engine, and an unmanned aerial vehicle (UAV) powered by an engine having the dual-fluid injection system. The dual-fluid injection system comprises a liquid fuel metering device and a fluid delivery device operating in tandem. A gas supply system comprising an air compressor and an air delivery path extending between the air compressor and the fluid delivery device is provided to supply pressurised air to the fluid delivery device. The gas supply system comprises an air compressor and an air delivery path extending between the air compressor and the fluid delivery device. A fuel supply system is adapted to deliver liquid fuel to the liquid fuel metering device. A fuel-air regulator is provided for regulating fuel pressure with reference to air pressure to establish and maintain a requisite pressure differential between the fuel pressure and the air pressure. The fuel-air regulator is located remotely from the fluid delivery device and more particularly in close proximity to the air compressor. In a preferred arrangement, the fuel-air regulator is mounted on or integrated with the air compressor or a part thereof.

A dual-fluid injection system for an internal combustion engine, and an unmanned aerial vehicle (UAV) powered by an engine having the dual-fluid injection system. The dual-fluid injection system comprises a liquid fuel metering device and a fluid delivery device operating in tandem. A gas supply system comprising an air compressor and an air delivery path extending between the air compressor and the fluid delivery device is provided to supply pressurised air to the fluid delivery device. The gas supply system comprises an air compressor and an air delivery path extending between the air compressor and the fluid delivery device. A fuel supply system is adapted to deliver liquid fuel to the liquid fuel metering device. A fuel-air regulator is provided for regulating fuel pressure with reference to air pressure to establish and maintain a requisite pressure differential between the fuel pressure and the air pressure. The fuel-air regulator is located remotely from the fluid delivery device and more particularly in close proximity to the air compressor. In a preferred arrangement, the fuel-air regulator is mounted on or integrated with the air compressor or a part thereof.

A liquid injector atomizer for direct injection in to the cylinder of an internal combustion engine is provided, with a supply of pressurized liquid a supply of pressurized gas, a body, and a nozzle with two or more orifices each for the liquid and the gas. Each orifice directs a jet of metered pressurized liquid or gas out of the injector body. At least two of the liquid jets are aimed at one or more collision points, where at least two gas jet streams collide at a same collision point or another collision point, thereby creating a finely atomized liquid.

A liquid injector atomizer for direct injection in to the cylinder of an internal combustion engine is provided, with a supply of pressurized liquid a supply of pressurized gas, a body, and a nozzle with two or more orifices each for the liquid and the gas. Each orifice directs a jet of metered pressurized liquid or gas out of the injector body. At least two of the liquid jets are aimed at one or more collision points, where at least two gas jet streams collide at a same collision point or another collision point, thereby creating a finely atomized liquid.

A fluid mixing device that includes a housing having a fuel inlet and at least one primary orifice positioned at the inlet, wherein the at least one orifice configured to disperse a stream of fuel into a plurality of fuel droplets. The plurality of fuel droplets contact a fuel impingement surface to break up the plurality of fuel droplets into a plurality of smaller secondary droplets and create a thin film of secondary droplets on the impingement surface. At least one pressurized air channel delivers an airflow into contact with the secondary droplets. The secondary droplets pass through a plurality of secondary outlet orifices to exit the housing. A size of the plurality of secondary droplets is reduced when passing out of the plurality of secondary orifices.

A fluid mixing device that includes a housing having a fuel inlet and at least one primary orifice positioned at the inlet, wherein the at least one orifice configured to disperse a stream of fuel into a plurality of fuel droplets. The plurality of fuel droplets contact a fuel impingement surface to break up the plurality of fuel droplets into a plurality of smaller secondary droplets and create a thin film of secondary droplets on the impingement surface. At least one pressurized air channel delivers an airflow into contact with the secondary droplets. The secondary droplets pass through a plurality of secondary outlet orifices to exit the housing. A size of the plurality of secondary droplets is reduced when passing out of the plurality of secondary orifices.

A method of controlling fuel delivery to an engine includes providing a fluid atomizer, a mechanically driven air compressor, a start up air source, and an air valve coupled between the mechanically driven air compressor and the start up air source, charging the start up air source, delivering compressed air from the start up air source to the fluid atomizer, providing an initial air/fluid mixture with the fluid atomizer, and operating the air valve to direct compressed air from the mechanically driven air compressor to the fluid atomizer.

A method of controlling fuel delivery to an engine includes providing a fluid atomizer, a mechanically driven air compressor, a start up air source, and an air valve coupled between the mechanically driven air compressor and the start up air source, charging the start up air source, delivering compressed air from the start up air source to the fluid atomizer, providing an initial air/fluid mixture with the fluid atomizer, and operating the air valve to direct compressed air from the mechanically driven air compressor to the fluid atomizer.