Internal combustion engine having a transitionally segregated combustion chamber

A combustion chamber assembly, comprising:

• a cylinder head assembly including an internal bore, an open end, a closed end, and an external block;
• a piston assembly adapted to reciprocate within the internal bore between a top dead center (TDC) position near the closed end and a bottom dead center (BDC) position, the piston assembly having a compression end facing the closed end, an outside diameter, a groove located at the outside diameter a crevice distance from the compression end, and a sealing ring positioned in the groove;
• a combustion chamber bounded by the compression end, the closed end, and the internal bore, and whose volume is dependent on the position of the compression end, wherein the combustion chamber is adapted to transition from unstratified to stratified each time the compression end travels from BDC toward TDC and reaches a stratified distance from the closed end, and the combustion chamber is adapted to transition from stratified to unstratified each time the compression end travels from TDC toward BDC and reaches the stratified distance from the closed end, and wherein the combustion chamber, when stratified, includes a central combustion region, a perimeter squish region, and a transfer passage between the central region and the perimeter squish region, where a sum of volumes of these regions and passage equals a volume of the combustion chamber, and when unstratified includes a single region, where a volume of the single region equals the volume of the combustion chamber;
• and
• a direct fuel injector mounted to the closed end and, when the combustion chamber is stratified, the direct fuel injector is positioned to inject fuel into the central combustion region,
• wherein the perimeter squish region includes a portion of the internal bore which is bounded by the compression end and closed end, and wherein the transfer passage is adapted to transfer gasses from the perimeter squish region to the central combustion region prior to the start of combustion.