Piston with combustion stabilizing bowl
A piston for engine may include an annular body including a combustion bowl defining a volume and surrounded on a top side thereof by an annular crown portion defining a top squish surface with include an inner edge defining an opening to the combustion bowl. The opening may include an area for combustion gases to enter the bowl during a compression stroke of the piston. The combustion bowl may include a reentrant surface that defines a tangent that forms a reentrant angle with the top squish surface. The reentrant angle may range from 28.0 degrees to 32.0 degrees. A ratio of a bowl volume to an area of the entry opening may ranges from 45 mm to 52 mm. A ratio of a bowl volume to the reentrant angle may range from 12 cc/deg to 15 cc/deg.
1 . A piston configured to reciprocate in a bore of an engine, the piston comprising:
an annular body including a combustion bowl defining a volume and surrounded on a top side thereof by an annular crown portion defining a top squish surface with an inner edge defining an opening to the combustion bowl, the opening having an area for combustion gases to enter the bowl during a compression stroke of the piston, wherein the combustion bowl comprises a reentrant surface that extends axially downwardly and radially outwardly relative to the top squish surface and defines a tangent that forms a reentrant angle with the top squish surface that ranges from 28.0 degrees to 32.0 degrees;
the combustion bowl further including a concave arcuate surface extending from the reentrant surface, a converging surface extending radially inward from the concave arcuate surface, a transition surface extending from the converging surface, a bottom extremity defining surface, and a cylindrical surface extending axially upwardly from the bottom extremity defining surface; and
a minimum diameter of the combustion bowl, axially below the opening to the combustion bowl, is defined by the cylindrical surface.
2 . The piston of claim 1 , wherein the reentrant surface is conical.
3 . The piston of claim 1 , wherein the combustion bowl comprises a swirl pocket having the reentrant surface and the concave arcuate surface extending from the reentrant surface and having a radius of curvature that ranges from 8.5 millimeters to 10.5 millimeters.
4 . The piston of claim 3 , wherein the converging surface extends toward a longitudinal axis, defining a lower tangent that forms an acute angle with the longitudinal axis that ranges from 18.0 degrees to 22.0 degrees.
5 . The piston of claim 4 , wherein the converging surface is conical.
6 . The piston of claim 5 , wherein the cylindrical surface extending axially downwardly from the converging surface, and the bottom extremity defining surface is concave and extends from the cylindrical surface, and the swirl pocket further comprises a convex arcuate surface extending upwardly from the concave bottom extremity defining surface to a flat plateau surface that is perpendicular to the longitudinal axis.
7 . The piston of claim 6 , wherein the swirl pocket further includes a radius connecting the converging surface to the cylindrical surface having a radius of curvature ranging from 13.0 millimeters to 17.0 millimeters, the concave bottom extremity defining surface has a radius of curvature that ranges from 8.0 millimeters to 12.0 millimeters, and the convex arcuate surface has a radius of curvature that ranges from 50.0 millimeters to 54.0 millimeters.