Gm Global Technolgoy Operations, Inc.

Kenneth Erich Schroeder

John B Fisher

Fanghui Shi

Zheng Ma

A compression ring assembly for a piston of an internal combustion engine includes a first compression ring and a second compression ring, with the second compression ring overlaid adjacent to and in abutting engagement with the first compression ring. When both the first compression ring and the second compression ring are uncompressed and in a free state, the second compression ring includes an outer second ring diameter that is greater than an outer first ring diameter of the first compression ring. Additionally, the first compression ring includes a first radial width that is greater than a second radial width of the second compression ring. A first gap of the first compression ring is positioned relative to a second gap of the second compression ring in a non-overlapping orientation.

Two-piece compression piston ring of an internal combustion engine

Disclosed is a piston having a top chamfer functioning as an oil reservoir, the top chamfer designed to reduce piston noise and friction. The top chamfer partially defines a tapered volume or cavity configured to enhance oil flow to the middle portions of the piston skirt so as to increase lubrication during piston up stroke and thereby reduce piston noise and friction.

Piston top chamfer design to reduce noise and friction

A piston, having a first side subject to major thrust loading and a second side subject to minor thrust loading, is provided. The piston has a crown portion and a first and second pin boss portion depending therefrom. An axially extending pin bore is provided within the first and second pin boss portions. A first axially extending slot is provided within the piston pin bore on the first side. Additionally, a second axially extending slot is provided within the piston pin bore on the second side of the piston. The second axially extending slot is positioned closer to the crown portion than the first axially extending slot. The first and second axially extending slots are generally concave in shape.

Piston having asymmetrical pin bore slot placement

A single point turning tool has a tip including a cutting edge with a tip radius and a linear portion added on one side of and slightly behind the point to form a cutting edge with a linear portion and a protruding portion. The protruding extends beyond the plane of the linear portion which, in turn, extends normal to a longitudinal axis on which the tip radius is centered. During manufacture of a piston, the turning tool is positioned with the linear portion aligned generally with the plane of the finished outer surface. The piston is turned while the tool cuts a helical path or turn around the skirt surface by advancing the tool each turn a desired dimension or lead that is greater than the width of the protruding portion but not greater than the combined widths of the linear and protruding portions. The resulting skirt surface is a series of sequentially adjacent turns, each of which includes a shallow valley, preferably with slightly sloping sides, and each turn has a width equal to the width of the protruding portion of the tool and an adjacent flat or linear portion having a width equal to the difference between the lead of the helix and the width of the adjacent valley.

Growing community of inventors

Sanford, MI, United States of America

Kenneth Erich Schroeder