Piston with local inorganic fiber reinforcement.

摘要

An engine piston is formed with a top crown surface and a top ring groove. An upper annular land surface is defined between the top ring groove and the edge of the top crown surface. The upper annular land surface and the side walls of the top ring groove are defined by a part of the piston which is formed of a matrix metal reinforced with inorganic fibers. The proportion of the inorganic fibers by volume in the reinforced part of the piston may optionally be approximately between 2% and 10%. A method for making such a piston includes forming a mass of inorganic fiber into an approximately cylindrical shape, placing it against the edge of the bottom surface of a hollow cylindrical lower mold, pouring molten metal into the lower mold to cover the inorganic fiber, sliding an upper mold into the lower mold and pressurizing the molten metal to infiltrate it between the inorganic fibers until complete solidification, removing the solidified mass of metal and entrapped inorganic fiber from the lower mold, and machining it to form a piston, with the fiber reinforced parts defining the upper ring groove side walls and the upper land surface.