Piston geometry for reduced smoke and cylinder head component temperatures

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 radially outer lip portion including a top squish surface, and
• the contoured combustion bowl includes a radially inner planar shelf surface that is spaced axially away from the top squish surface a first axial distance, and that is connected to the top squish surface by a concave blend that is tangent to the radially inner planar shelf surface and extends axially upwardly to the top squish surface, and
• a swirl pocket that includes a bottom concave arcuate surface extending axially downwardly and radially inwardly from the radially inner planar shelf surface and defining a lower axial extremity that is spaced axially away from the top squish surface a second axial distance, and a ratio of the first axial distance to the second axial distance ranges from 10% to 15%;
• wherein the swirl pocket includes a first conical surface that is interposed radially and axially between the radially inner planar shelf surface and the bottom concave arcuate surface.

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 radially outer lip portion including a top squish surface defining a first radial dimension, and
• the contoured combustion bowl includes a radially inner planar shelf surface that is spaced axially away from the top squish surface a first axial distance, and that is connected to the top squish surface by an undulating transitional surface that is tangent to the radially inner planar shelf surface and extends radially outwardly and axially downwardly to a trough point and then axially upwardly and radially outwardly to the top squish surface, and
• a swirl pocket that includes a bottom concave arcuate surface extending axially downwardly and radially inwardly from the radially inner planar shelf surface and defining a lower axial extremity that is spaced axially away from the top squish surface a second axial distance, and a ratio of the first axial distance to the second axial distance ranges from 10% to 15%.