Piston design feature to minimize periodic second land pressure variation

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, and a circumferential direction, the annular body including
• a top squish surface of the crown portion, and a circumferential annular wall extending downwardly axially from the top squish surface;
• and
• a skirt extending downwardly axially from the circumferential annular wall defining a skirt circumferential extent;
• wherein the circumferential annular wall defines a first groove that is spaced axially away from the top squish surface, forming a first land, and a second groove spaced axially away from the first groove, forming a second land, and a first blend extending axially, and radially from the second groove a circumferential extent about the longitudinal axis that is less than 360 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, and a circumferential direction, the annular body including
• a top squish surface of the crown portion, and a circumferential annular wall extending downwardly axially from the top squish surface;
• and
• a skirt extending downwardly axially from the circumferential annular wall;
• wherein the circumferential annular wall defines a first piston ring receiving groove that is spaced away from the top squish surface, an upper land extending from the first piston ring receiving groove, and a lower land extending from the first piston ring receiving groove, and only a bottom blend connecting the lower land to the first piston ring receiving groove and extends circumferentially at least as much as the skirt circumferential extent but less than 360 degrees.