Cooling structure of diesel engine piston

A diesel engine piston comprising:

• a piston body having a longitudinal axis, a top face, and a generally cylindrical outer periphery, with a reentrant combustion chamber formed in said top face;
• an annular cooling cavity formed in said piston body circumferentially around and outwardly of an outer periphery of said reentrant combustion chamber, said annular cooling cavity having a top, a bottom, and an inner annular wall surface extending between the top and the bottom of said cooling cavity;
• a cooling liquid inlet passageway formed in said piston body whereby cooling liquid can be supplied through said cooling liquid inlet passageway to said annular cooling cavity;
• and
• at least one cooling liquid outlet formed in said piston body whereby cooling liquid can be withdrawn from said annular cooling cavity through said at least one cooling liquid outlet;
• wherein a top portion of said inner annular wall surface of said cooling cavity is located adjacent said top face and has a smaller diameter, in a plane perpendicular to said longitudinal axis, than a bottom portion of said inner annular wall surface;
• and
• wherein a distribution member is formed in said cooling cavity directly above said cooling liquid inlet passageway so as to divide a flow of cooling liquid from said cooling liquid inlet passageway into two streams for passage through said cooling cavity in opposite directions.