Abstract: Operating an engine system includes calculating a crank angle timing term corresponding to an in-cylinder temperature sufficient for autoignition of a first fuel injected at a first injection location. Operating an engine system further includes calculating, based on the crank angle timing term, at least one of an injection amount or an injection duration, to increase the in-cylinder temperature sufficiently via burning of the first fuel to ignite a second fuel injected into a mixture of the first fuel and pressurized intake air. The first fuel may include a blend of dimethyl ether (DME), methanol (MeOH), and water. Based on expected progression of in-cylinder temperatures, and fuel injection amount and/or duration based thereon, desirable controllability of combustion phasing and/or other combustion properties may be realized.

Abstract: Operating a hybrid power system for a machine includes combusting a direct injected gaseous hydrogen fuel in an engine operating an electrical generator, and increasing a load demand of the hybrid power system. Operating the hybrid power system further includes operating an electrical-assist compressor to supply an increased airflow into the engine based on an increased engine power demand to satisfy the increased load demand. Air-fuel equivalence ratio of the engine (so-called “lambda”) is maintained at a ratio of about 2 or greater to limit NOx emissions, and between a hydrogen fuel misfire limit and a hydrogen fuel preignition limit. Related apparatus and control logic is also disclosed.

Abstract: An engine includes a piston movable in a cylinder and having a combustion bowl, and an annular rim forming a scoop extending axisymmetrically around a piston center axis. A fuel injector tip extends into the cylinder and includes a first orifice set and a second orifice set offset from one another and offset from the piston center axis. A plurality of orifice-rim distances are defined between orifices in the second orifice set and an annular rim of the piston. The orifices in the second orifice set having a range of orifice sizes varied in direct relation to the respective orifice-rim distances. Related methodology is also disclosed.

Abstract: A gaseous fuel engine includes an engine housing having a cylinder block with a combustion cylinder therein, and an engine head including an intake port, an exhaust port, a fuel port, and an igniter bore, each extending to a fire deck. The gaseous fuel engine includes a fuel admission valve movable to close and open the fuel port. A non-axisymmetric clearance is defined between an inner port surface and the fuel admission valve and directionally biases a flow of gaseous fuel from the fuel port. Related methodology is also disclosed.

Abstract: Operating an engine system includes autoigniting a first fuel including a plurality of liquid fuels premixed with air, to trigger ignition of a direct-injected main fuel in a first engine cycle, and receiving data indicative of an undesired heat release of combustion of the first fuel. The undesired heat release may include an undesired heat release rate (HRR) modality such as a multistage combustion. Relative amounts of the plurality of the liquid fuels are varied and admitted to the cylinder in a second engine cycle, and the first fuel having the varied relative amounts autoignited to trigger ignition of the direct-injected main fuel in the second engine cycle. The undesired heat release can be limited in the second engine cycle based on the varied relative amounts of the liquid fuels. The first fuel may include a blend of dimethyl ether (DME), methanol (MeOH), and water. The direct-injected main fuel may include MeOH and water. Related apparatus and control logic is also disclosed.

Abstract: An engine includes a piston movable in a cylinder and having a combustion bowl, and an annular rim forming a scoop extending axisymmetrically around a piston center axis. A fuel injector tip extends into the cylinder and includes a first orifice set and a second orifice set offset from one another and offset from the piston center axis. A plurality of orifice-rim distances are defined between orifices in the second orifice set and an annular rim of the piston. The orifices in the second orifice set having a range of orifice sizes varied in direct relation to the respective orifice-rim distances. Related methodology is also disclosed.

Abstract: A gaseous fuel engine includes an engine housing having a cylinder block with a combustion cylinder therein, and an engine head including an intake port, an exhaust port, a fuel port, and an igniter bore, each extending to a fire deck. The gaseous fuel engine includes a fuel admission valve movable to close and open the fuel port. A non-axisymmetric clearance is defined between an inner port surface and the fuel admission valve and directionally biases a flow of gaseous fuel from the fuel port. Related methodology is also disclosed.

Abstract: An exhaust heater system includes an exhaust heater and an air supply tube disposed within the exhaust heater. Relatively hot exhaust gas from an engine is directed into the exhaust heater, whereby heat from the exhaust heats the interior of the air supply tube. The heat partially vaporizes liquid methanol injected into the air supply tube. To control the amount of heating, the exhaust can be directed to the air supply tube as well as an exhaust bypass, whereby exhaust directed to the exhaust bypass does not heat the interior of the air supply tube.

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: An engine system includes a first cylinder including a first piston, a second cylinder including a second piston, and a fuel injector fluidly connected to the first cylinder. The first cylinder is a combustion cylinder, and the second cylinder is an expansion cylinder. The second cylinder is fluidly connected to the first cylinder when the first piston is in at least one position in the first cylinder. The fuel injector is configured to deliver hydrogen gas to the first cylinder.

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 piston for an internal combustion engine includes a crown portion having a bowl that includes a plurality of protrusions. Each of the plurality of protrusions includes a first side surface and a second side surface. Other features including at least one ledge formed between protrusions in segments, and a generally flat, inward facing surface on the protrusions may also be used.

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.