Abstract: A fuel injector includes a nozzle assembly having a nozzle case, and a concentric check assembly within the nozzle case. Transfer passages are formed in an outer check of the check assembly, and spray orifices are formed in the nozzle case. A fuel volume is formed between the outer check and an inner check, and the inner check is movable to fluidly connect the transfer passages to the fuel volume. The outer check is rotatable between a first angular orientation and a second angular orientation to fluidly connect separate sets of the transfer passages to separate sets of the spray orifices. Spray ducts are in spray path alignment with at least one of the sets of spray orifices.

Abstract: An engine system includes an engine housing having a cylinder block and a cylinder head. An intake opening and an exhaust opening and an igniter opening are formed in a fire deck surface of the cylinder head. A plurality of always-open fuel admission ports are fluidly connected to a combustion chamber and arranged in at least one of the cylinder block or the cylinder head. The always-open fuel admission ports convey a gaseous fuel such as a gaseous hydrogen fuel, a gaseous hydrocarbon fuel, or still others, to the combustion chamber.

Abstract: Operating an engine includes injecting a first charge of liquid fuel using a first set of nozzle outlets in a fuel injector, and injecting a second charge of liquid fuel using a second set of nozzle outlets in a fuel injector. The first charge is autoignited in a first engine cycle, and the second charge is autoignited in a second engine cycle, and may be used to pilot ignite a charge of gaseous fuel. Operating the engine further includes limiting errors in targeting of the second charge of liquid fuel caused by transitioning the engine from a first combination to a second combination of speed, load, and boost, by varying an injection pressure of the liquid fuel from the first engine cycle to the second engine cycle.

Abstract: A fuel injector includes an injector housing having a nozzle assembly with a nozzle piece, and a nested check assembly of an outer check and an inner check. Spray orifices are formed in the nozzle piece in a first orifice set equipped with a first spray duct set and a second orifice set equipped with a second spray duct set. The inner check can be opened to spray fuel from the first orifice set and the outer check can be opened to spray fuel from both the first orifice set and the second orifice set. The outer check is non-rotating while the inner check can be permitted to rotate during service. Spray ducts associated with the first orifice set may have a different duct length and duct inside diameter than spray ducts associated with the second orifice set. The first orifice set may include lower-flow spray orifices and the second orifice set may include higher-flow spray orifices. Related methodology is also disclosed.

Abstract: A fuel injector includes an injector housing having a nozzle assembly with a nozzle piece, and a nested check assembly of an outer check and an inner check. Spray orifices are formed in the nozzle piece in a first orifice set equipped with a first spray duct set and a second orifice set equipped with a second spray duct set. The inner check can be opened to spray fuel from the first orifice set and the outer check can be opened to spray fuel from both the first orifice set and the second orifice set. The outer check is non-rotating while the inner check can be permitted to rotate during service. Spray ducts associated with the first orifice set may have a different duct length and duct inside diameter than spray ducts associated with the second orifice set. The first orifice set may include lower-flow spray orifices and the second orifice set may include higher-flow spray orifices. Related methodology is also disclosed.

Abstract: An igniter for a dual fuel engine includes an igniter body having spray outlets formed in a nozzle and arranged in a plurality of outlet sets. The igniter further includes a plurality of outlet checks each movable in the igniter body to open and close the spray outlets in a respective one of the plurality of outlet sets, and spark electrodes mounted to the igniter body and forming a spark gap. The outlet sets vary set-to-set in at least one of spray angle, spray outlet number, or spray outlet size. Related methodology is disclosed.

Abstract: An internal combustion engine system includes an engine housing having a combustion cylinder, and a piston movable within the combustion cylinder to increase a pressure therein to an autoignition threshold for injected fuel. The piston includes a piston crown having a combustion face forming a combustion bowl, and varied in profile to form jet-jet interaction limiters at locations offset from fuel spray jet paths from a fuel injector. The jet-jet interaction limiters include a bowl component and a step component protruding, respectively, within the combustion bowl and a step located transitioning between the combustion bowl and a circumferential rim of the piston. Limiting jet-jet interaction limits soot production in exhaust produced by the engine.

Abstract: A fuel injector includes a nozzle assembly having a nozzle case, and a concentric check assembly within the nozzle case. Transfer passages are formed in an outer check of the check assembly, and spray orifices are formed in the nozzle case. A fuel volume is formed between the outer check and an inner check, and the inner check is movable to fluidly connect the transfer passages to the fuel volume. The outer check is rotatable between a first angular orientation and a second angular orientation to fluidly connect separate sets of the transfer passages to separate sets of the spray orifices. Spray ducts are in spray path alignment with at least one of the sets of spray orifices.

Abstract: A liquid fuel injector such as for a dual fuel system in an internal combustion engine includes two-way injection control valves for controlling twin outlet checks. A first set of orifices are arranged in an A-F-Z pattern, and a second set of orifices are arranged in an A-F-Z pattern, within the fuel injector, among a high-pressure inlet passage, a low-pressure space, and first and second outlet check control chambers, respectively. A common nozzle supply cavity is fluidly connected to the high-pressure inlet passage and supplies each of two sets of nozzle outlets opened and closed by the twin outlet checks.

Abstract: An internal combustion engine system includes an engine housing having a combustion cylinder, and a piston movable within the combustion cylinder to increase a pressure therein to an autoignition threshold for injected fuel. The piston includes a piston crown having a combustion face forming a combustion bowl, and varied in profile to form jet-jet interaction limiters at locations offset from fuel spray jet paths from a fuel injector. The jet-jet interaction limiters include a bowl component and a step component protruding, respectively, within the combustion bowl and a step located transitioning between the combustion bowl and a circumferential rim of the piston. Limiting jet-jet interaction limits soot production in exhaust produced by the engine.

Abstract: A piston for an internal combustion engine includes a piston having a bowl surface forming a combustion bowl, a rim surface forming an annular rim, and a gallery surface exposed to a backside cooling gallery of the piston. The bowl surface forms a bowl profile varied circumferentially around a piston center axis, and the gallery surface forms a gallery profile that is varied circumferentially around the piston center axis and is congruous with the bowl profile. The gallery surface is concave to the combustion bowl, convex to the backside cooling gallery, and forms no edges exposed within the backside cooling gallery. A wall formed between the combustion bowl and the backside cooling gallery has a heat-dissipation wall thickness defined by the varied bowl profile and the varied gallery profile.

Abstract: Operating an engine includes injecting a first charge of liquid fuel using a first set of nozzle outlets in a fuel injector, and injecting a second charge of liquid fuel using a second set of nozzle outlets in a fuel injector. The first charge is autoignited in a first engine cycle, and the second charge is autoignited in a second engine cycle, and may be used to pilot ignite a charge of gaseous fuel. Operating the engine further includes limiting errors in targeting of the second charge of liquid fuel caused by transitioning the engine from a first combination to a second combination of speed, load, and boost, by varying an injection pressure of the liquid fuel from the first engine cycle to the second engine cycle.

Abstract: Operating an engine includes injecting a first charge of liquid fuel using a first set of nozzle outlets in a fuel injector, and injecting a second charge of liquid fuel using a second set of nozzle outlets in a fuel injector. The first charge is autoignited in a first engine cycle, and the second charge is autoignited in a second engine cycle, and may be used to pilot ignite a charge of gaseous fuel. Operating the engine further includes limiting errors in targeting of the second charge of liquid fuel caused by transitioning the engine from a first combination to a second combination of speed, load, and boost, by varying an injection pressure of the liquid fuel from the first engine cycle to the second engine cycle.

Abstract: A method of controlling a dual fuel engine system includes adjusting a phasing control parameter such as air-fuel ratio (AFR), based on a phasing signal to limit an error in a phasing of combustion of gaseous fuel. The cylinder is switched to a dual fuel liquid pilot-ignited mode by commanding direct injection of an early pilot shot of liquid fuel, based on the adjustment to the phasing control parameter, and production of a spark to ignite gaseous fuel in the cylinder. Switching the cylinder to the dual fuel liquid pilot-ignited mode is completed by commanding direct injection of an early pilot shot and a second pilot shot of liquid fuel to ignite gaseous fuel in response to combustion of the early and second pilot shots in the cylinder.

Abstract: A combustion control system for a dual fuel engine includes a combustion control unit structured to receive phasing data for combustion of a main charge of gaseous fuel ignited by way of pilot shots of a liquid fuel, output a pilot fueling command based on the phasing data, and output a valve timing command. The combustion control unit is further structured to vary a phasing of combustion of a main charge of a gaseous fuel ignited by pilot shots of a liquid fuel based on an adjustment to at least one of a pilot shot delivery parameter or a valve timing parameter such as intake valve closing timing from a first engine cycle to a second engine cycle. Control of the intake valve timing can be based on a main pilot shot timing error.

Abstract: A fuel system for an internal combustion engine includes a fuel injector having a nozzle with first and second sets of spray orifices formed therein. The fuel injector also includes a first and a second outlet check movable to open and close the first and second sets of spray orifices. Spray plume ducts are supported at fixed orientations relative to a nozzle of the fuel injector, and each are oriented in-line with a center axis defined by one of the spray orifices. The spray plume ducts may be directly attached to the fuel injector or to a duct carrier mounted to an engine head.

Abstract: A fuel system for an internal combustion engine includes a fuel injector having a nozzle with first and second sets of spray orifices formed therein. The fuel injector also includes a first and a second outlet check movable to open and close the first and second sets of spray orifices. Spray plume ducts are supported at fixed orientations relative to a nozzle of the fuel injector, and each are oriented in-line with a center axis defined by one of the spray orifices. The spray plume ducts may be directly attached to the fuel injector or to a duct carrier mounted to an engine head.

Abstract: A component of a piston may include a crown portion configured to face a flame deck surface disposed at one end of a cylinder bore in which the piston is configured to reciprocate, such that a combustion chamber is defined within the cylinder bore and between a top surface of the crown portion and the flame deck surface. The component may include an indent formed in the top surface. The indent may be aligned with a fuel jet centerline along which a fuel jet is to be injected into the combustion chamber. The indent may include a first arcuate indent portion, that curves in a first direction from a center of the crown portion, and a second arcuate indent portion that curves in a second direction from a break in a reentrant feature that overhangs the first arcuate indent portion. The component may be included in an internal combustion engine.

Abstract: Operating a dual fuel engine system includes injecting an early shot and a second shot of a liquid fuel into a cylinder after a late closing timing of an intake valve, and producing a first and a second pilot flame based on ignition of the early shot and the second shot of liquid fuel. The early shot of liquid fuel is targeted such that a distribution of ignition points of the first pilot flame is biased outwardly of a combustion bowl in the piston. Propagation of the first and second pilot flames from geometrically distinct ignition locations rapidly increases pressure and temperature in the cylinder to provide fast combustion of a lean mixture of a gaseous fuel and air in a main charge in the cylinder.

Abstract: Operating a dual fuel engine system includes injecting an early shot and a second shot of a liquid fuel into a cylinder after a late closing timing of an intake valve, and producing a first and a second pilot flame based on ignition of the early shot and the second shot of liquid fuel. The early shot of liquid fuel is targeted such that a distribution of ignition points of the first pilot flame is biased outwardly of a combustion bowl in the piston. Propagation of the first and second pilot flames from geometrically distinct ignition locations rapidly increases pressure and temperature in the cylinder to provide fast combustion of a lean mixture of a gaseous fuel and air in a main charge in the cylinder.