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.

An internal combustion engine for a motor vehicle has at least one cylinder, a cylinder head, and a piston which is movably mounted in the cylinder and has a combustion chamber side which delimits a combustion chamber with the cylinder head and the cylinder. The cylinder head has a combustion chamber roof, in which at least two valve seats for at least one inlet valve and at least one outlet valve are provided. The combustion chamber roof has at least one arched cylinder head section which is arranged between the at least two valve seats and points away from the combustion chamber.

A diesel engine includes a cylinder head, a cylinder sleeve, a piston, an injector, and a combustion chamber. The top side of the piston includes an annular top surface, an annular collision belt and an annular cavity. The collision belt includes a collision surface, an upper guide surface, and a lower guide surface. An annular throat is formed between the upper guide surface and the cylinder head. The collision belt divides the combustion chamber into a headspace and a central portion. The volume of the headspace is more than three times of the volume of the central portion. A major portion of the fuel jet injected by the injector is directed into the headspace. The results are faster mixing of fuel and air and complete combustion in the combustion chamber, and a reduction of fuel consumption rate by 2%. A method for fuel distribution and combustion is also disclosed.

A combustion chamber structure for an engine includes a combustion chamber where SI combustion by spark ignition and CI combustion by self-ignition are conducted. A crown surface includes a cavity recessed to have a bowl-shape, and a pair of raised portions. The cavity includes a bottom portion which is a lower region of the recessed part, the bottom portion having an outer circumferential edge which is circular in a top view. With a height of the raised portion relative to a height position of a deepest portion of the cavity being represented as H1 and a diameter of an outer circumferential edge of the bottom portion of the cavity being represented as D, H1/D as a ratio of the height H1 of the raised portion to the diameter D of the cavity is set to be in a range of 0.05 or more and 0.36 or less.

A top surface of the piston includes a first region. A heat shielding film is formed on the first area. The top surface further includes a second region. There is no heat shielding film formed on the second region. Instead, the second area is mirror-finished. The top surface includes a central portion. A valve recess portion is formed on an intake side of the central portion. A squish portion is formed the intake side of the valve recess portion. The first area includes at least the central portion. The second area includes at least the squish portion.

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.

An engine system comprising an internal combustion engine and a turbocharger, where a diameter of the at least one intake valve is greater than a diameter of the at least one exhaust valve, the salient angle of the piston bowl is at least 10 degrees, the ratio between the piston bowl opening diameter and the piston bowl depth is approximately 0.5 to 2.0, the intake valve opens before top dead center on an exhaust stroke of the internal combustion engine and closes before bottom dead center of an intake stroke of the internal combustion engine, and the turbocharger has a combined efficiency of more than 50%.

A piston may have an annular body including a crown portion defining a longitudinal axis, a radial direction perpendicular to the longitudinal axis, a plane containing the longitudinal axis and the radial direction, and a contoured combustion bowl. In the plane containing the longitudinal axis and the radial direction, the crown portion includes a radially outer squish surface, and a swirl pocket having a reentrant surface that extends axially downwardly and radially outwardly from the squish surface defining a tangent that forms a reentrant angle with the squish surface that ranges from 53.0 degrees to 57.0 degrees.

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 diesel engine includes a cylinder head, a cylinder sleeve, a piston, an injector, and a combustion chamber. The top side of the piston includes an annular top surface, an annular collision belt and an annular cavity. The collision belt includes a collision surface, an upper guide surface, and a lower guide surface. An annular throat is formed between the upper guide surface and the cylinder head. The collision belt divides the combustion chamber into a headspace and a central portion. The volume of the headspace is more than three times of the volume of the central portion. A major portion of the fuel jet injected by the injector is directed into the headspace. The results are faster mixing of fuel and air and complete combustion in the combustion chamber, and a reduction of fuel consumption rate by 2%. A method for fuel distribution and combustion is also disclosed.