Abstract: A piston assembly and connecting rod therefor is provided. The connecting rod has an elongate body extending to an end for operable attachment to a piston. The end has a wrist pin bore extending between opposite sides of the body. The wrist pin bore has a wavy profile extending between the sides. The wavy profile has at least one concave surface with a valley extending along a circumferential direction of the wrist pin bore and convex surfaces having peaks extending along a circumferential direction of the wrist pin bore on laterally opposite sides of the valley. The peaks and valleys cooperate to form a smooth load gradient and uniform lubrication flow across the interface region between the wrist pin bore and the wrist pin extending therethrough.

Abstract: A piston assembly and wrist pin therefor provide a method for controlling rotation of the wrist pin with respective piston pin bores and connecting rod small end wrist pin bore. The wrist pin has a cylindrical body with opposite end portions spaced axially from one another by a central portion and a through bore of varying internal diameter. The through bore has first diameter and second diameters, wherein the first diameter is less than the second diameter. The first diameter is defined in one of the central portion or the opposite end portions, while the second diameter is defined in the other of the central portion or the opposite end portions. The first diameter transitions to the second diameter generally between the small end of the connecting rod and the pin bores of the piston.

Abstract: A piston assembly and connecting rod therefor is provided. The connecting rod has an elongate body extending to an end for operable attachment to a piston. The end has a wrist pin bore extending between opposite sides of the body. The wrist pin bore has a wavy profile extending between the sides. The wavy profile has at least one concave surface with a valley extending along a circumferential direction of the wrist pin bore and convex surfaces having peaks extending along a circumferential direction of the wrist pin bore on laterally opposite sides of the valley. The peaks and valleys cooperate to form a smooth load gradient and uniform lubrication flow across the interface region between the wrist pin bore and the wrist pin extending therethrough.

Abstract: A piston assembly and wrist pin therefor provide a method for controlling rotation of the wrist pin with respective piston pin bores and connecting rod small end wrist pin bore. The wrist pin has a cylindrical body with opposite end portions spaced axially from one another by a central portion and a through bore of varying internal diameter. The through bore has first diameter and second diameters, wherein the first diameter is less than the second diameter. The first diameter is defined in one of the central portion or the opposite end portions, while the second diameter is defined in the other of the central portion or the opposite end portions. The first diameter transitions to the second diameter generally between the small end of the connecting rod and the pin bores of the piston.

Abstract: A monobloc piston has at least two steel parts welded together to define an inner cooling gallery. An outer ring belt is spaced from an inner annular support wall and is joined by a combustion bowl and a lower wall. A pair of pin bosses have axially aligned pin bores. A skirt is formed as one immovable piece with the pin bores. The piston has the following dimensional relationships: ISMD=42-55% of BD, where ISMD is a mean diameter on the inner support wall and BD is an outer diameter of the ring belt wall, ISW=3-8% of BD, where ISW is a sectional width of the inner support wall, CH>53% of BD where CH is a compression height measured between the pin bore axis and the upper surface, TLH>4% of BD, where TLH is a top land height measured between the top of the upper ring groove and the upper surface, SL=30-80% of BD, where SL is a length of the skirt measured between the upper and lower ends of the skirt, SW=2.5-6.

Abstract: A monobloc piston has at least two steel parts welded together to define an inner cooling gallery. An outer ring belt is spaced from an inner annular support wall and is joined by a combustion bowl and a lower wall. A pair of pin bosses have axially aligned pin bores. A skirt is formed as one immovable piece with the pin bores.

Abstract: An articulated piston includes a crown and a separate skirt joined in articulated manner to the pin bosses of the crown by a wrist pin. The skirt has opposing thrust surfaces which contact the wall of a cylinder bore of an engine when the piston experiences side loading during operation. The thrust surfaces have a vertical profile which is generally symmetrical about a center plane containing the axis of a pin bore of the skirt. The profile includes tapered end sections and a wide, shallow central depressed region. Under normal operation, the depressed region channels lubricant to the pin bores. The twin peaked profile distributes side loads and stress above and below the pin bore plane and under heavy load, the depressed region bows outwardly presenting a flat, full contact surface between the peaked regions for decreasing the wear load on the thrust surfaces.

Abstract: An articulated piston includes a crown and a separate skirt joined in articulated manner to the pin bosses of the crown by a wrist pin. The skirt has opposing thrust surfaces which contact the wall of a cylinder bore of an engine when the piston experiences side loading during operation. The thrust surfaces have a vertical profile which is generally symmetrical about a center plane containing the axis of a pin bore of the skirt. The profile includes tapered end sections and a wide, shallow central depressed region. Under normal operation, the depressed region channels lubricant to the pin bores. The twin peaked profile distributes side loads and stress above and below the pin bore plane and under heavy load, the depressed region bows outwardly presenting a flat, full contact surface between the peaked regions for decreasing the wear load on the thrust surfaces.