The present invention relates to a combustion chamber structure of an engine configured to inject fuel in a predetermined operation range in a period from a second half of a compression stroke until a first half of an expansion stroke to perform ignition after a compression top dead center. The combustion chamber structure includes: a piston including a cavity; a fuel injection valve provided at a middle portion of the piston; and a spark plug provided at a radially outer side of the middle portion of the piston and an upper side of the cavity. The cavity is formed by a curved surface having curvature that becomes larger as the curved surface extends toward the radially outer side. A tangential direction of an edge end portion of the curved surface intersects with a combustion chamber ceiling radially outward of the spark plug.

A method for producing a piston for an internal combustion engine may include the steps of: producing a piston upper part from a first blank via a deformation process; producing a piston lower part from a second blank via at least one of a deformation process and a casting process; connecting the first blank of the piston upper part and the second blank of the piston lower part to form a piston body via a welding process; and performing at least one of a secondary machining process and a finish machining process of the piston body to produce the piston.

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.

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).

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 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 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.

A piston crown is provided for a piston in an internal combustion engine arrangement that includes a cylinder, the piston crown having a piston bowl surface adapted for facing a combustion chamber in the cylinder, wherein the piston bowl surface including a circumferential rim portion, a floor portion connected to and surrounded by the circumferential rim portion, a plurality of circumferentially spaced protrusions in the circumferential rim portion, at least one spray impingement portion, located between two adjacent protrusions. The spray impingement portion includes a reflection surface, being defined by that each possible normal to the reflection surface is directed towards a central axis of the piston, and forming an angle being within a range of a constant angle 10 with the central axis, wherein the constant angle is at least 50.