The present invention is a fuel injection method for a compression-ignition internal-combustion engine running in single-fuel or multi-fuel mode. The method, in a single-fuel mode, injects liquid fuel (Fuel1) into lower zone (Z1) and/or upper zone (Z2) of the combustion chamber and, in a multi-fuel mode, provides in the chamber mixing of an oxidizer with another fuel (Fuel2) and injection of liquid fuel (Fuel1) into lower zone (Z1) or both zones (Z1, Z2) of the combustion chamber.

The present invention relates to a compression-ignition direct-injection internal-combustion engine comprising at least a cylinder (10), a cylinder head (12) carrying fuel injection (14) projecting the fuel in at least two fuel jet sheets (36, 38) with different sheet angles (A1, A2), a piston (16) sliding in the cylinder, a combustion chamber (34) limited on one side by upper face (44) of the piston comprising a projection (48) extending in the direction of the cylinder head and arranged in the center of a concave bowl (46) with at least two mixing zones (Z1, Z2), and piston cooler (76) housed in the material of the piston. According to the invention, the piston cooler comprises at least one circumferential gallery (78, 82) concentric to piston bowl (46) and arranged opposite at least one mixing zone (Z1, Z2).

A piston includes a piston body having an outer cylindrical surface and defined along a longitudinal piston center axis. The piston further includes a piston bowl with a half section profile with a bowl entry extending radially from the longitudinal piston center axis; a bowl recess extending radially from the bowl entry; and a soot shelf extending from the bowl recess to define a soot shelf axial height (H) and a soot shelf radial width (W). The soot shelf includes an inner step being formed by an inner step base surface extending radially from the bowl recess; an outer step being formed by a step shoulder surface extending axially from the inner step base surface and an outer step base surface extending radially from the step shoulder surface; and a soot shelf shoulder surface extending axially from outer step base surface to the end perimeter surface.

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.

The present invention is a compression-ignition direct-injection internal-combustion engine comprising at least a cylinder (10), a cylinder head (12) carrying fuel injection means (14), a piston (16) sliding in the cylinder, a combustion chamber (34) limited on one side by an upper face (44) of the piston comprising a projection (48) extending in the direction of the cylinder head and located in a center of a concave bowl (46). The engine comprises injection projecting fuel in at least two fuel jet sheets. One of the zones comprises a toroidal volume (64) having center B with a flat bottom (56) into which fuel jets (40) of the lower sheet are injected so that an axis C1 of the lower sheet jets is contained between center B and projection (48).

A variable-compression ratio direct-injection internal-combustion engine comprising at least a cylinder (10), a cylinder head (12) carrying a fuel injection means (14) spraying fuel in a single sheet (34) of fuel jets (36), a piston (16) sliding in this cylinder, and a combustion chamber (32) delimited on one side by upper face (42) of the piston comprising a projection (46) rising up towards the cylinder head and arranged in the cent of a concave bowl (44). According to the invention, the combustion chamber comprises at least two mixing zones (Z1, Z2) into which fuel jets (36) are injected, one (Z1) of the zones being used for a maximum compression ratio (Tmax) and the other (Z2) zone being used for a minimum compression ratio (Tmini).

A piston for an internal combustion engine includes a piston body forming a crown portion and a skirt portion, the crown portion forming a generally concave bowl extending symmetrically around the piston body with respect to an axis of symmetry of the crown portion. The bowl forms a first lip and a second lip that are arranged in a stepped configuration along a side margin of the bowl. A depressed ledge having a generally annular shape is further formed in the crown portion, the depressed ledge including a flat, annular surface extending along a plane that is parallel to a plane defined by the generally flat crown surface.

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.

A piston for an engine may include a piston body. The piston body may include a piston crown disposed symmetrically about a central longitudinal axis of the piston. A combustion bowl may be recessed into the piston body and may be offset axially inwardly with respect to the piston crown. A central bowl apex may protrude axially from the combustion bowl and may be offset axially inwardly with respect to the piston crown. A first bowl apex may protrude axially from the combustion bowl and may be disposed radially inwardly with respect to the piston crown. A second bowl apex may protrude axially from the combustion bowl and may be disposed radially inwardly with respect to the first bowl apex and may be radially between the first bowl apex and the central bowl apex. The second bowl apex may be offset axially inwardly with respect to the central bowl apex.

A combustion system for an internal combustion engine includes a cylinder having a cylinder wall defining a bore, a piston disposed inside the bore, a combustion chamber delimited by a cylinder head, the cylinder wall, and the piston. The piston includes a piston bowl defining a floor portion, and at least one scooped recess extending radially outwardly from a periphery of the piston bowl. The internal combustion engine further includes a fuel injector configured to inject fuel into the combustion chamber as a plurality of fuel jets at a main injection timing such that each fuel jet contacts the floor portion of the piston bowl and follows a profile of the piston bowl and enter the at least one scooped recess. Furthermore, at least one of the plurality of is deflected by the at least one scooped recess away from the cylinder wall.