An insert device includes a body having an upper body portion configured to couple with a cylinder head of an engine cylinder and a lower body portion extending from the upper body portion toward a combustion chamber of the engine cylinder. The body includes an interior surface extending around a central volume positioned to receive liquid fuel from a fuel injector. The body includes gas inlet channels and fuel-and-gas mixture outlet channels. The gas inlet channels direct gas into the central volume where the gas mixes with the liquid fuel to form the fuel-and-gas mixture. The fuel-and-gas mixture outlet channels direct the mixture into the combustion chamber. The interior surface includes concave surface portions between the inlet channels and the outlet channels along a center axis of the body that are shaped to direct the gas into the central volume toward the liquid fuel in the central volume.

A mixing structure can include a body having first conduits, mixture conduits, and second conduits extending through the body to the internal volume. The first conduits may be closer to a first side of the body than the mixture conduits and the second conduits. The second conduits may closer to another side of the body than the first conduits and the mixture conduits. The internal volume may receive liquid streams from an injector. The first conduits and the second conduits may receive gas streams from outside the body. The body may thermally modify the gas streams and entrain the gas streams into the liquid streams in the internal volume. The mixture conduits may be positioned to direct the gas streams entrained into the liquid streams out of the body in directions directed toward the second side of the body and away from the first side of the body.

A fuel and gas mixing structure for an engine is provided. This mixing structure includes a body configured to be positioned between a fuel injector and a cylinder of an engine. The body defines an interior volume that is configured to receive gas (e.g., air) from outside the body and to receive one or more streams of fuel from the fuel injector in the interior volume. The body also includes one or more upper channels and one or more lower channels that are configured to provide a substantially similar amount of flow relative to each other to the interior volume The body also defines one or more mixture conduits configured to conduct plumes of the fuel and gas, while mixing, from the interior volume to one or more exit ports and therethrough to the cylinder.

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.

This piston for a diesel engine includes: a bottom portion that has a deepest combustion chamber bottom in the combustion chamber; a circumferential protrusion that is provided around an entire circumference of a circumferential wall between the bottom portion and a top surface of the piston and protrudes toward an intersection (P0) of a center line of the piston and the top surface in a cross-sectional view that includes the center line; an inclination portion that inclines closer to the top surface toward an outer side in a radial direction from the circumferential protrusion; and a rising portion that rises from the inclination portion toward the top surface.

A fuel injector includes an injector housing having a fuel connector, and an outer housing surface extending around a longitudinal axis of the injector housing. The outer housing surface includes a cylindrical upper section, a cylindrical lower section, and a middle section. The fuel connector defines a connector axis oriented normal to a longitudinal axis of the injector housing and extending between a first connector end attached to the middle section, and a terminal connector end radially outward of the outer housing surface and having therein a fuel inlet. The fuel connector includes an outer connector surface having an unthreaded base section, and an externally threaded end section adjacent to the terminal connector end.

Systems and methods regarding a ducted fuel injection (DFI) combustion system for an internal combustion engine can control an injection timing of a fuel injector to output fuel injections through at least one duct and into a combustion chamber of the internal combustion engine. The injection timing can include one or more pilot injections according to a predetermined range before top dead center (BTDC) for a combustion cycle; and a main injection into the combustion chamber for the combustion cycle after all of the one or more pilot injections. A first amount of the fuel injected for the main injection can be greater than a second amount of fuel injected for the one or more pilot injections. The predetermined range before top dead center (BTDC) of the one or more pilot injections can be from 85 to 40 degrees BTDC.

Operating an engine includes moving a piston in a combustion chamber between a bottom dead center position and a top dead center position in an engine cycle. A fuel is injected into the combustion chamber through a plurality of sets of nozzle outlets varied set-to-set with respect to outlet size and spray angle. Spray jets of the injected fuel are propagated in an impingement-limiting fuel spray pattern that is based on the set-to-set variation in outlet size and spray angle so as to limit dissipation of heat from combustion of the injected fuel to material of the engine by way of a thermal barrier coating (TBC) upon a surface of the combustion chamber.

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 reciprocating combustion engine includes at least one cylinder, in which a reciprocating piston is arranged back and forth movable. The reciprocating combustion engine includes a pin structure arranged on the combustion chamber side in the area of the cylinder head or the piston bottom. Due to the pin structure, local peak temperatures can be avoided during the combustion process, so that NOx emissions can be avoided or at least greatly reduced. A motor vehicle, for example a commercial vehicle, includes a reciprocating combustion engine.