Piston bowl with spray jet targets

A piston for a direct injection engine, the piston comprising a bowl at an upper end, the bowl forming a portion of a combustion chamber, wherein the bowl has an inner surface that defines a volume configured to receive a fuel-air mixture, the inner surface of the bowl including:

• at least one surface feature that forms at least one edge portion which protrudes into the bowl volume as a target for fuel spray, the edge portion defined by two or more surface portions that intersect at a radius of 0.1 mm-1.5 mm and said at least one surface feature forms at least one edge portion which is recessed into the bowl volume, the edge portions configured as targets for fuel spray, the edge portion defined by two or more surface portions that intersect at a radius of 0.1 mm-1.5 mm.

A method of operating an internal combustion engine having at least one cylinder and a piston slidably disposed within the at least one cylinder, the method comprising:

• moving the piston toward a top dead center position during a compression stroke;
• spraying a fuel and air mixture into a piston bowl recessed in said piston, wherein the bowl has an inner surface that defines a volume configured to receive said fuel-air mixture, the inner surface of the bowl including at least one surface feature that forms at least one edge portion as a target for fuel spray, the edge portion defined by two or more surface portions that intersect at a radius of 0.1 mm-1.5 mm;
• wherein said surface feature including said edge portion redirects said fuel-air mixture upon impact of said target to provide additional fuel-air mixing.