Patent ID: 8499735

Claim:
An internal combustion engine with a combustion chamber, comprising: an engine body including an engine cylinder, a cylinder head forming an inner surface of the combustion chamber and at least one intake port; a piston positioned for reciprocal movement in the engine cylinder between a bottom dead center position and a top dead center position, the piston including a piston crown comprising an upper surface facing the combustion chamber, the piston crown containing a piston bowl ( 6 ) formed by an outwardly opening cavity, the piston bowl comprising a projecting portion having a distal end and an inner bowl floor section extending downwardly at a positive inner bowl floor angle (α) from a plane perpendicular to an axis of reciprocation of the piston, the piston bowl further comprising an outwardly flared outer bowl section having a concave curvilinear shape in cross section; an injector mounted on the engine body adjacent the projecting portion of the piston bowl to inject fuel into the combustion chamber with high injection pressure, the injector comprising a plurality of orifices arranged to form fuel spray plumes, which during progress become ignited flames that impinge within predetermined impingement areas on the outer bowl section, wherein the impingement areas are in the outer bowl section during most of the injection and in that substantially half way between the impingement areas in the outer bowl section and in a plane substantially perpendicular to the reciprocal movement are arranged a first type of protrusions protruding into the combustion chamber and having a smooth form adapted 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, and where each of the protrusions has a shape of a longitudinal ridge that extends only in the outer bowl area in a plane substantially parallel to the reciprocal movement.