Abstract: Disclosed is a low drag piston for a reciprocating engine that comprises a piston head that reduces mechanical and viscous friction while improving oil lubrication and thermal load dissipation throughout the piston stroke. The piston comprises a cylindrical crown and lower skirt area such that these elements are the only surfaces in contact with the cylinder walls and support a plurality of piston rings, while the interior skirt region is recessed inward in a concave shape to reduce drag, friction and thermal expansion interferences. An additional oil control ring increases oil outflow to further reduce friction and drag, while the pin boss that holds the connection between the piston head and the connecting rods is recessed inward within the inwardly concave central portion.

Abstract: Disclosed is a low drag piston for a reciprocating engine that comprises a piston head that reduces mechanical and viscous friction while improving oil lubrication and thermal load dissipation throughout the piston stroke. The piston comprises a cylindrical crown and lower skirt area such that these elements are the only surfaces in contact with the cylinder walls and support a plurality of piston rings, while the interior skirt region is recessed inward in a concave shape to reduce drag, friction and thermal expansion interferences. An additional oil control ring increases oil outflow to further reduce friction and drag, while the pin boss that holds the connection between the piston head and the connecting rods is recessed inward within the inwardly concave central portion.