Low compression natural gas engine piston bowl for improved combustion stability

A piston configured to reciprocate in the bore of an engine, the piston comprising:

• 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;
• wherein in the plane containing the longitudinal axis and the radial direction
• the crown portion includes a top squish surface, and
• a swirl pocket having a reentrant surface that extends axially downwardly and radially outwardly from the top squish surface defining a tangent that forms a reentrant angle with the top squish surface that ranges from 53.0 degrees to 57.0 degrees;
• the swirl pocket further including:
• a concave arcuate surface extending from the reentrant surface, defining a radius of curvature that ranges from 8.5 millimeters to 10.5 millimeters in the plane containing the longitudinal axis and the radial direction;
• and
• a converging surface that extends radially inwardly from the concave arcuate surface toward the longitudinal axis, defining a lower tangent that forms an acute angle with the longitudinal axis in the plane containing the longitudinal axis and the radial direction that ranges from 18.0 degrees to 22.0 degrees.

A piston configured to reciprocate in the bore of an engine, the piston comprising:

• 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;
• wherein in the plane containing the longitudinal axis and the radial direction
• the crown portion includes a top squish surface, and
• a swirl pocket having a reentrant surface that extends axially downwardly and radially outwardly from the top squish surface defining a tangent that forms a reentrant angle with the top squish surface;
• the swirl pocket further including:
• a concave arcuate surface extending from the reentrant surface, a bottom concave arcuate surface defining a bottom extremity of the swirl pocket, and a convex arcuate surface extending between the concave arcuate surface and the bottom concave arcuate surface;
• and
• a converging surface that extends radially inwardly from the concave arcuate surface toward the longitudinal axis, defining a lower tangent that forms an acute angle with the longitudinal axis in the plane containing the longitudinal axis and the radial direction.