A piston for a reciprocating piston machine includes a piston crown, a piston recess, and an annular groove formed in the piston crown. The annular groove extends in a radial direction of the piston outwards and a cross-section of the annular groove has a half-teardrop shape. The half-teardrop shape has a first radius and a second radius where the second radius is directly contiguous with the first radius outwards in the radial direction of the piston and where the second radius is greater than the first radius.

A piston for a diesel engine, includes a piston body having a generally planar crown and a skirt extending from the crown. A stepped combustion bowl is recessed in the crown and includes an outer bowl recessed relative to the crown and an inner bowl recessed relative to the outer bowl.

An ignition chamber of a combustion engine, the ignition chamber comprising: a piston having a piston bottom surface and a cylinder head having a cylinder head surface, the ignition chamber having an ignition chamber axis wherein one of said piston bottom surface and said cylinder head surface includes at least one depression and an ignition device is disposed in said ignition chamber and extends along said ignition chamber axis, said ignition device is configured to cause a cylindrical ignition impulse along said ignition chamber axis so as to create radial impulse components that are redirected by said depression so as to move in a direction longitudinal to said combustion chamber axis.

A combustion chamber structure for an internal combustion engine includes, in a piston top part, a concave portion formed eccentrically with respect to a cylinder center axis, and a tapered portion that connects an upper end face of the piston top part and a side face of the concave portion. The tapered portion is formed so that a tapered portion volume (volume of a space formed between the tapered portion and an upper wall surface of the combustion chamber) in a first portion of the piston top part is greater than a tapered portion volume in a second portion that is nearer than the first portion to an eccentric direction of the concave portion from the cylinder center axis.

A piston for an engine may include a body. The body may extend between a first and second axial region. A piston crown may be disposed at the first axial region symmetrically about a central longitudinal axis of the piston. A first bowl may be recessed into the body and may include a first curved wall transitioning into the piston crown at a bowl lip. The bowl lip may include a bowl lip diameter. The first curved wall may include a first wall diameter greater than the bowl lip diameter. A second bowl may be recessed into the body and disposed axially inwardly from the first bowl. The second bowl may include a second curved wall transitioning into the first bowl at a peak. The peak may include a peak diameter. The second curved wall may include a second wall diameter greater than the peak diameter.

A piston and an engine are provided that includes various precise configuration parameters, including dimensions, shape and/or relative positioning of combustion chamber features. More particularly, configuration parameters for a piston crown and a piston bowl located within the piston crown are provided. The piston bowl configuration results in a combustion process that yields decreased heat transfer to a cylinder head of the internal combustion engine as well as reduced NOx emissions.

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.

Gaseous fuel injection pressures are normally less than liquid fuel injection pressures, resulting in reduced gaseous fuel jet momentum and mixing. A combustion system for an internal combustion engine comprises an intake port and valve, a cylinder and a piston that cooperate to provide a quiescent combustion chamber. The piston includes a re-entrant type piston bowl comprising an outer periphery and a protuberance emanating from the outer periphery. A fuel injector is configured to directly introduce a gaseous fuel into the combustion chamber and an ignition source is provided for igniting the gaseous fuel. A controller actuates the fuel injector such that a gaseous fuel jet is directed towards and splits upon impacting the protuberance forming first and second fuel plumes. The first fuel plume is redirected towards a first mixing zone adjacent a cylinder head and the second fuel plume redirected towards a second mixing zone adjacent the piston 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 this cylinder, a combustion chamber (34) having on one side an upper face (44) of the piston comprising a projection (48) extending in the direction of the cylinder head and located at the center of a concave bowl (46). The engine comprises an injector projecting fuel in at least two fuel jet sheets with sheet injection angles (A1, A2), a lower sheet (36) of jet axis C1 and an upper sheet (38) of jet axis C2, at least two mixing zones (Z1, Z2) of the combustion chamber. According to the invention, one of the zones comprises a toroidal volume (64) of center B into which fuel jets (40) of the lower jet are injected in such a way that axis C1 of the lower jet is contained between center B and projection (48).

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.