A piston crown for a combustion system is disclosed. The piston crown includes a piston bowl having a circumferential recess and a plurality of first recesses arranged spaced apart from each other along a circumferential direction. The circumferential recess is disposed proximate to a circumference of the piston crown. Each recess of the plurality of the first recesses extends between a center of the piston crown and the circumferential recess, and a width and a depth of each recess of the plurality of first recesses are extended along a radial direction for an entire length of each recess of the plurality of first recesses.

Methods and systems are provided for a piston. In one example, a system may comprise a plurality of first protrusions and a plurality of second protrusions working in tandem to confine an injection to a radial zone defined by the protrusions.

The invention relates to an air-compressing internal combustion engine, comprising at least one piston (1) having a combustion chamber trough (3) substantially rotationally symmetrical to a piston axis (2), which has a trough bottom (4) with a substantially cone-like elevation (5) and a circumferential trough wall (6), wherein the trough wall (6) forms a substantially torus-like first section (6a) having a maximum inner first trough diameter (d1), a second section (6b) having a minimum inner second trough diameter (d2) smaller than the inner first trough diameter (d1), and a third section (6c), whereinas seen in a meridian section of the piston (1)the first section (6a) has a concave first radius of curvature (R1) and the second section (6b) has a convex second radius of curvature (R2), and wherein the third section (6c) forms a first annular surface (8) adjoining the second section (6b) and a second annular surface (9) terminating in the piston end surface (7), which second annular surface (9) defines an angle () with the first annular surface (8), wherein the first annular surface (8) and the second annular surface (9) are formed to be inclined to a normal plane () on the piston axis (2), and wherein in the transition between the first annular surface (8) and second annular surface (9) an edge (11) is formed with a defined third radius of curvature (R3),

In order to prevent soot formation phenomena, it is provided that, as viewed in a meridian section of the piston (1), the first annular surface (8) together with a normal plane () on the piston axis (2) forms a first angle () between 10 and 20, preferably 15.2.

A piston for an internal combustion engine includes a crown portion having a bowl that includes a plurality of protrusions. Each of the plurality of protrusions includes a first side surface and a second side surface, the first side surface having a generally concave shape, the second side surface having a generally flat or convex shape.

A piston crown for a combustion system is disclosed. The piston crown includes a piston bowl having a circumferential recess and a plurality of first recesses arranged spaced apart from each other along a circumferential direction. The circumferential recess is disposed proximate to a circumference of the piston crown. Each recess of the plurality of the first recesses extends between a center of the piston crown and the circumferential recess, and a width and a depth of each recess of the plurality of first recesses are extended along a radial direction for an entire length of each recess of the plurality of first recesses.

A piston combustion chamber structure of an engine includes two or more independent combustion chambers separated from each other and dented on an upper portion of a piston head in axial and circumferential directions. Each of the two or more independent combustion chambers comprises an outer wall and a bottom surface. Independent combustion chambers adjacent to each other among the two or more independent combustion chambers are partitioned by a partition wall. The partition wall has a slant surface such that a squish flowing in the circumferential direction can be generated.

A combustion control device for a compression autoignition engine includes an engine, a state quantity setting device, a spark plug, a controller, and a sensor. The spark plug receives a control signal from the controller and ignites air-fuel mixture at predetermined ignition timing such that the ignited air-fuel mixture is combusted by flame propagation and then unburned air-fuel mixture in a combustion chamber is combusted by autoignition. The controller outputs a control signal to an injector such that, in a compression stroke, fuel is injected at specific timing at which a line obtained by extending an axis of each hole of the injector overlaps with a specific portion including an opening edge of a cavity in an upper surface of a piston.

Methods and systems are provided for a piston. In one example, a system may comprise a plurality of first protrusions and a plurality of second protrusions working in tandem to confine an injection to a radial zone defined by the protrusions.

A piston for a diesel engine includes a piston body having a skirt and crown. The piston body has portions defining an outer combustion bowl and an inner combustion bowl within the piston body through the crown. The outer combustion bowl has a curved annular side wall extending from the crown surface and an annular flat shelf extending from the curved annular side wall. The new stepped bowl design integrates a bottom profile with smoothly varying curvature and a sharp step at the top. The annular flat shelf is recessed a distance in the range of 2.5-4.5 millimeters from a line coplanar with the crown surface. The piston body defines an outer convex curved surface connecting the curved annular side wall to the crown surface. The outer convex curved surface has a radius of curvature in the range of 0.25-0.75 millimeter.

Systems, devices, and methods described herein provide one or more radical chemicals generators (RCGs) and/or mini-chambers (M-Cs) that can be used to provide enhanced radical ignition (ERI) in an internal combustion engine. RCGs as described herein can include quenching systems (QSs) that can be configured to quench a flame of combustion products to produce a jet of partial combustion products containing radical species (RS). The jet of partial combustion products can be injected to a main combustion chamber (MCC) of an engine to induce ERI. ERI can proceed under leaner fuel conditions and lower temperatures compared to those needed for conventional thermally induced, fuel oxidation chain initiation reaction processes.