Piston and engine

A piston, comprising a throat, a first annular groove, an internal oil cooling channel, a first annular protrusion, and a second annular protrusion;

• wherein the throat is provided at a top of the piston, the first annular groove is provided on an outer circumferential surface of the piston, the internal oil cooling channel is annular and provided between the throat and the first annular groove, the first annular protrusion protrudes from an inner annular wall of the internal oil cooling channel, a guide contour is provided on a upper part of the first annular protrusion, the guide contour is disposed obliquely downward from the inner annular wall of the internal oil cooling channel to an outer annular wall of the internal oil cooling channel, the second annular protrusion protrudes from the outer annular wall of the internal oil cooling channel, the second annular protrusion is located below the first annular protrusion, the first annular protrusion is located on the inner annular wall of the internal oil cooling channel and below the throat, the second annular protrusion is located on the outer annular wall of the internal oil cooling channel, and the first annular protrusion is provided at a position corresponding to the first annular groove.