MONOLITHIC, GALLERYLESS PISTON AND METHOD OF CONSTRUCTION THEREOF

摘要

A galleryless steel piston for an internal combustion engine is provided. The piston has a monolithic piston body including an upper wall forming an upper combustion surface with first and second portions. The first portion extends annularly along an outer periphery of the upper wall and the second portion defines a combustion bowl. The piston further includes undercrown surface located directly opposite the combustion bowl with an exposed 2-dimensional surface area allowing for contact of cooling oil. The exposed 2-dimensional surface area ranges from 25 to 60 percent of a cross-sectional area defined by a maximum outer diameter of the piston body. To further enhance cooling, a portion of the undercrown surface is concave or convex, such that oil is channeled during reciprocation of the piston from one side to the opposite side of the piston.

主权项

1. A piston for an internal combustion engine, comprising:
a piston body extending along a central longitudinal axis; said piston body having an upper wall forming an upper combustion surface and an annular ring belt depending from said upper combustion surface; said upper combustion surface having first and second portions, said first portion extending annularly along an outer periphery of said upper wall and said second portion forming a combustion bowl depending radially inwardly from said first portion; said upper wall having an undercrown surface formed on an underside thereof, said undercrown surface located opposite said second portion of said upper combustion surface and radially inwardly of said ring belt; said piston body including a pair of skirt panels depending from said ring belt; said piston body including a pair of pin bosses spaced from one another by said skirt panels and providing a pair of laterally spaced pin bores; said piston body being free of a cooling gallery along said undercrown surface; and said undercrown surface having an exposed 2-dimensional surface area, as viewed looking along said central longitudinal axis, ranging from 25 to 60 percent of a cross-sectional area defined by a maximum outer diameter of said piston body.