Methods and systems are provided for a surface structure for a piston. In one example, the surface structure is located on at least a portion of the piston.

The disclosure provides a piston crown for a piston mountable in a combustion cylinder of an internal combustion engine. The piston crown includes a top annular surface. Radially inside the top annular surface is a piston bowl for guiding fuel injected into the combustion cylinder. The piston bowl includes a frusto-conical lip chamfer surface at a throat of the piston bowl next to the annular surface. In diametric cross-section the lip chamfer surface has a radius of at least 30 mm, preferably 30 mm.

A piston comprises a crown portion with a contoured bowl having a reentrant surface extending from the top squish surface that connects to a lower sidewall surface that connects to a swirl pocket surface disposed adjacent the bottom bowl surface.

A heat shield film M1 is formed on entire are of the side surface 20b. A heat shield film M2 is formed entire area of the top surface 12a and the bottom surface 20c. The heat shield films M1 and M2 are mainly composed of porous alumina. The difference between the heat shield films M1 and M2 is in film thickness. The film thickness of the heat shield film M1 is from 20 to 60 m and that of the heat shield film M2 is from 60 to 150 m.

A galleryless piston having a reduced weight and a reduced operating temperature is provided. The piston includes an undercrown surface exposed from an underside of the piston, a ring belt, pin bosses each presenting a pin bore, and skirt panels depending from the ring belt and coupled to the pin bosses by strut. The piston further includes an inner undercrown region extending along the undercrown surface and surrounded by the skirt panels, the struts, and the pin bosses. The piston also includes outer pockets each extending along the undercrown surface and each surrounded by a portion of the ring belt, one of the pin bosses, and the struts coupling the one pin boss to the skirt panels. Cutouts are located in the pin bosses above the pin bores to increase the area of the undercrown surface and thus allow cooling oil to remove more heat from the undercrown surface.

A piston comprises a crown portion with a contoured bowl having a reentrant surface extending from the top squish surface that connects to a lower sidewall surface that connects to a swirl pocket surface disposed adjacent the bottom bowl surface.

A piston for an internal combustion engine, such as a high-pressure direct injection (HPDI) diesel/gas internal combustion engine. The piston has a piston recess, in particular an omega piston recess. The piston has a piston crown face which is provided so as to extend annularly about a centre axis (M) of the piston. The piston has a plurality of piston stages, which are provided so as to extend annularly about the centre axis (M) and which are arranged between the piston crown face and the piston recess. The piston geometry can lead to an increase of the degree of engine efficiency with a simultaneous reduction of the exhaust emissions.

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).

An engine includes: a piston including a cavity; a cylinder head configured to form a combustion chamber having a pent roof shape; a fuel injection valve configured to inject fuel from a second half of a compression stroke until a first half of an expansion stroke; and a spark plug arranged at a position corresponding to an upper side of the cavity. Injection openings are arranged in a circumferential direction surrounding a longitudinal axis of the valve. The combustion chamber at a compression top dead center is divided into a plurality of fuel injection regions, located in respective injection directions of the injection openings, by vertical surfaces extending radially from the longitudinal axis through a middle between adjacent injection openings. When a volume of the fuel injection region located in the injection direction of the injection opening is large, an opening area of the injection opening is large.