An opposed-piston engine according to an embodiment is a first fuel injection device configured to inject fuel from a circumferential wall surface of at least one cylinder into the cylinder, and a second fuel injection device disposed to be displaced in a circumferential direction so as to be opposite to the first fuel injection device across an axial center of the cylinder. Each of the first fuel injection device and the second fuel injection device includes a plurality of injection holes having different injection directions, in a cross-section orthogonal to the axial direction. A direction directed by a first downstream injection hole is configured to pass through a second injection region, and a direction directed by a second downstream injection hole is configured to pass through a first injection region.

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.

A piston for an internal combustion engine includes a piston bowl. The piston bowl has a half section profile that includes a bowl entry extending radially from the longitudinal piston center axis, a first bowl recess extending radially from the bowl entry and defining a bowl depth and a first radius of curvature, a second bowl recess extending radially from a first bowl recess to an end perimeter surface and defining a second radius of curvature, a bowl lip defined by the first bowl recess and the second bowl recess, and a bowl edge defined by the second bowl recess and the end perimeter surface. The first bowl recess further defines a first bowl recess exit angle at the bowl lip. The second bowl recess further defines a second bowl recess exit angle at the bowl edge.

A piston includes a swirl pocket that extends radially from the radially outer lip portion to a lower axial extremity spaced away from the radially outer lip portion a first axial distance. A convex arcuate surface extends downwardly and inwardly from the radially outer lip portion, a concave arcuate surface extends to the lower axial extremity from the convex arcuate surface, and a conical portion extends upwardly and inwardly from the concave arcuate surface to an apex that is spaced a second axial distance from the radially outer lip portion that is less than the first axial distance.

In an opposed-piston engine, a piston has a top land. The piston top land has a non-cylindrical shape which affords more clearance with a piston bore to thrust and anti-thrust sides than to front-facing and rear facing sides.

Apparatuses, systems and method for utilizing multi-zoned combustion chambers (and/or multiple combustion chambers) for achieving compression ignition (and/or spark-assisted or fuel-assisted compression ignition) in an internal combustion engine are provided. In addition, improved apparatuses, systems and methods for achieving and/or controlling compression ignition (and/or spark-assisted or fuel-assisted compression ignition) in a “Siamese cylinder” internal combustion engine are provided.

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.

A piston for an internal combustion engine includes a piston bowl. The piston bowl has a half section profile that includes a bowl entry extending radially from the longitudinal piston center axis, a first bowl recess extending radially from the bowl entry and defining a bowl depth and a first radius of curvature, a second bowl recess extending radially from a first bowl recess to an end perimeter surface and defining a second radius of curvature, a bowl lip defined by the first bowl recess and the second bowl recess, and a bowl edge defined by the second bowl recess and the end perimeter surface. The first bowl recess further defines a first bowl recess exit angle at the bowl lip. The second bowl recess further defines a second bowl recess exit angle at the bowl edge.

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.