A piston for a cylinder for an internal combustion engine has a piston bowl surface adapted for facing a combustion chamber of the cylinder, the piston bowl surface being provided with a thermal barrier coating layer, wherein the thermal barrier coating layer is provided on a plurality of circumferentially spaced surface parts of the piston bowl surface. A method for producing a piston for a cylinder for an internal combustion engine includes the steps of providing a piston for a cylinder for an internal combustion engine, the piston having a piston bowl surface adapted for facing a combustion chamber of the cylinder, and providing the piston bowl surface with a thermal barrier coating layer, wherein the step of providing the thermal barrier coating layer is made on a plurality of circumferentially spaced surface parts of the piston bowl surface.

The present invention is a compression-ignition direct-injection internal-combustion engine comprising at least a cylinder, a cylinder head carrying fuel injection, a piston sliding in the cylinder, a combustion chamber limited on one side by upper face of the piston comprising a projection extending in the direction of the cylinder head and in the center of a concave bowl (46) with at least two mixing zones. The fuel injection projects fuel in at least two fuel jet sheets with different sheet angles, with a lower sheet having a jet axis C1 for one zone and an upper sheet having a jet axis for the other zone. The injection feeds fuel into the combustion chamber with a different flow rate for each sheet for dedicated targeting in the mixing zones of the combustion chamber.

A piston and an engine including the same are provided. The piston includes an upper surface that is formed at an upper portion; a bowl that is concavely formed at the upper surface; a plurality of protruding portions that are separated by a predetermined distance along an edge of the bowl; and a central portion that is protruded upward at the center of the bowl.

A piston including a piston crown, the piston crown defining a combustion bowl with a bowl base and bottom surface. A failure initiation structure is provided on the bottom surface of the combustion bowl to initiate favorable fracture at predetermined loads. Such favorable fracture may lead to the a separation of a fragment of the bowl base from the combustion bowl when a predetermined load or pressure is exceeded within the combustion bowl.

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).

An internal combustion engine includes a piston and a fuel injection valve. The fuel injection valve includes a first injection hole, a second injection hole, a first needle configured to open and close the first injection hole, and a second needle configured to open and close the second injection hole. The first injection hole and the second injection hole are configured such that a portion of a fuel spray injected from the first injection hole and a portion of a fuel spray injected from the second injection hole overlap each other at a position apart at a predetermined distance from a side wall of a cavity of the piston. The second needle is configured to start operation in order to open the second injection hole after a predetermined time has elapsed from a point of time when the first needle starts operation in order to open the first injection hole.

A fuel injection valve has first injection holes, second injection holes, a first needle that opens and closes the first injection holes, and a second needle. The fuel injection valve is arranged such that a part of fuel injected from the first injection hole and a part of fuel injected from the second injection hole are gathered together at a position spaced from the side wall of the cavity by a predetermined distance. The second needle starts operating to open the second injection holes, after a predetermined time elapses from a point in time at which the first needle starts operating to open the first injection holes.

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 crown for a piston of an internal combustion engine, the piston crown extending in an axial direction along a central axis and in a radial direction outwardly from the central axis. The piston crown comprises an annular surface at a first end of the piston crown in the axial direction; and a piston bowl located radially within the annular surface and recessed relative to the first end of the piston crown. The piston bowl comprises a raised floor in a radially central region of the piston bowl; an arcuate surface located radially outward relative to the raised floor; and a lip chamfer surface extending radially outwardly from the arcuate surface and radially inwardly from the annular surface. A radially inmost portion of the lip chamfer surface is radially inside the radially outermost portion of the arcuate surface. A bowl maximum radius, R.sub.max, is defined as a distance in the radial direction between the central axis of the piston crown and an innermost edge of the annular surface. A bowl height, H, is defined as a distance in the axial direction between the annular surface and a surface of the piston bowl furthest from the annular surface. A lip re-entrancy angle is defined as an acute angle between a line extending in the radial direction at the first end of the piston crown and a tangent to the arcuate surface closest to the first end of the piston crown. The bowl maximum radius, R.sub.max, is between 2.3 and 3.2 times the bowl height, H, and the lip re-entrancy angle is between 40 and 80.

A piston and an engine including the same are provided. The piston includes an upper surface that is formed at an upper portion; a bowl that is concavely formed at the upper surface; a plurality of protruding portions that are separated by a predetermined distance along an edge of the bowl; and a central portion that is protruded upward at the center of the bowl.