Piston bowl geometry, cuff and top land interaction for reduced hydrocarbons, improved combustion efficiency, and piston temperature

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, and
• a swirl pocket that extends radially from the radially outer lip portion and defines a lower axial extremity that is spaced axially away from the radially outer lip portion a first axial distance, and the swirl pocket includes a convex arcuate surface extending axially downwardly and radially inwardly from the radially outer lip portion, a concave arcuate surface extending axially downwardly to the lower axial extremity, and radially inwardly from the convex arcuate surface, a conical portion that extends axially upwardly and radially inwardly from the concave arcuate surface to an apex, the apex being spaced a second axial distance from the radially outer lip portion that is less than the first axial distance, and the radially outer lip portion defines a bowl rim diameter defined by a tangent to the concave arcuate surface in the plane intersecting with a planar squish surface of the radially outer lip portion, the planar squish surface extending planarly and fully circumferentially around the longitudinal axis, and a ratio of the first axial distance to the bowl rim diameter ranges from 0.185 to 0.197.

A combustion chamber of an engine comprising:

• an annular cylinder liner defining a bore of the engine with a bore diameter, a longitudinal axis, a radial direction perpendicular to the longitudinal axis;
• and
• a piston configured to reciprocate in the bore of the engine, the piston including a crown portion defining 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, and a swirl pocket that extends radially from the radially outer lip portion and defines a lower axial extremity that is spaced axially away from the radially outer lip portion a first axial distance, and the swirl pocket includes a convex arcuate surface extending axially downwardly and radially inwardly from the radially outer lip portion, a concave arcuate surface extending axially downwardly to the lower axial extremity, and radially inwardly from the convex arcuate surface, a conical portion that extends axially upwardly and radially inwardly from the concave arcuate surface to an apex, the apex being spaced a second axial distance from the radially outer lip portion that is less than the first axial distance, and the radially outer lip portion defines a bowl rim diameter defined by a tangent to the concave arcuate surface that intersects a planar squish surface of the radially outer lip portion in the plane, the planar squish surface extending planarly around the longitudinal axis and a ratio of the bowl rim diameter to the bore diameter ranges from 0.805 to 0.815;
• wherein the cylinder liner defines an axially upper and radially inner counterbore, and further comprising a cuff that is disposed in the axially upper and radially inner counterbore.