Abstract: A piston is positioned for reciprocal movement in a combustion engine cylinder. Half way between flame plume impingement areas are arranged a first type of protrusions protruding into the combustion chamber and having a smooth form adapted for preserving kinetic energy in a flame plume. Each of the first type of protrusions has a shape of a longitudinal ridge that extends only in the outer bowl area. The first type of protrusions have a left side flank and a right side flank of the ridge when seen from the injector. The left side flank is formed differently compared to the right side flank in order to redirect the movement of a flame plume progressing towards the left side flank in a plane perpendicular to the reciprocal movement, differently compared to corresponding flame plume progressing, towards the right side flank.

Abstract: A piston is arranged for reciprocal movement in a combustion engine cylinder. Protrusions are or a ridge is arranged half way between flame plume impingement areas in a plane perpendicular to the reciprocal movement and protrude to the combustion chamber having a smooth form adapted for preserving kinetic energy in a flame plume. The protrusion or ridge includes a left side flank, a top section and a right side flank, and a transition section between each of the side flanks and the top section, the transition section including a deflection edge in order to minimize flow losses.

Abstract: A combustion chamber in an engine includes a piston and an injector with plurality of orifices arranged to inject spray/flame plumes, which impinge on a piston outer bowl section during most of the injection. Between spray/flame plume impingement areas and in a plane substantially perpendicular to reciprocal piston movement are arranged a first type of protrusions protruding into the combustion chamber, having a smooth form for preserving kinetic energy in the flame and for redirecting circumferential flame progress mainly towards a center axis of the piston with minimal flame-to-flame interaction. A second type of protrusions are arranged in the impingement areas, being adapted for redirecting flame progress into a circumferential flame progress direction in a plane substantially perpendicular to the reciprocal piston movement and with minimal flame-to-piston wall interaction and minimal kinetic energy loss.

Abstract: An internal combustion engine includes a combustion chamber, at least one intake port for directing intake air into the combustion chamber with no/low swirling; a piston with piston bowl, an injector with plurality of orifices arranged to inject fuel with high injection pressure to form spray plumes, each of the plurality of orifices having a central axis oriented at a positive spray angle sufficient to cause the spray/flame to impinge on a piston outer bowl section and a curvilinear shape of the outer bowl section is such that a reflection angle of the impingement of the central axis is positive during at least start of injection in order to increase balance between vertical upwardly directed and tangential movements of the spray/flame and to preserve mixing energy late in the combustion cycle for increased soot oxidation.

Abstract: A combustion chamber in an engine includes a piston and an injector with plurality of orifices arranged to inject spray/flame plumes, which impinge on a piston outer bowl section during most of the injection. Between spray/flame plume impingement areas and in a plane substantially perpendicular to reciprocal piston movement are arranged a first type of protrusions protruding into the combustion chamber, having a smooth form for preserving kinetic energy in the flame and for redirecting circumferential flame progress mainly towards a center axis of the piston with minimal flame-to-flame interaction. A second type of protrusions are arranged in the impingement areas, being adapted for redirecting flame progress into a circumferential flame progress direction in a plane substantially perpendicular to the reciprocal piston movement and with minimal flame-to-piston wall interaction and minimal kinetic energy loss.

Abstract: An internal combustion engine includes a combustion chamber, at least one intake port for directing intake air into the combustion chamber with no/low swirling; a piston with piston bowl, an injector with plurality of orifices arranged to inject fuel with high injection pressure to form spray plumes, each of the plurality of orifices having a central axis oriented at a positive spray angle sufficient to cause the spray/flame to impinge on a piston outer bowl section and a curvilinear shape of the outer bowl section is such that a reflection angle of the impingement of the central axis is positive during at least start of injection in order to increase balance between vertical upwardly directed and tangential movements of the spray/flame and to preserve mixing energy late in the combustion cycle for increased soot oxidation.