A vehicle internal combustion piston and method of construction thereof are provided. The piston includes piston body extending along a central longitudinal axis, having an upper combustion wall forming an upper combustion surface and an undercrown surface opposite the upper combustion surface. An annular ring belt region depends from the upper combustion surface, a pair of skirt panels depend from the ring belt region, and a pair of pin bosses depend from the undercrown surface to provide laterally spaced pin bores aligned along a pin bore axis for receipt of a wrist pin. The undercrown surface forms a central undercrown region, and a portion of either an open outer cooling gallery, a sealed outer cooling gallery, or an outer galleryless region. A coating comprising a base layer including nickel and a catalyst layer including rhodium is applied to the undercrown surface.

An internal combustion engine includes an engine main body defining a cylinder bore, a piston received in the cylinder bore, and a crankshaft rotatably supported by the engine main body and connected with the piston via a connecting rod, the piston including a skirt. The cylinder bore includes a first region defined as a range along the cylinder axial line on a side of a top dead center from a first piston position, and a second region defined as a range along the cylinder axial line on a side of the bottom dead center from a second piston position closer to the bottom dead center than the first piston position, and a connection region positioned between the first and second regions. A diameter of the cylinder bore is smaller in the first region than in the second region, and the connection region connects the first and second regions smoothly.

A one-piece piston having an investment or other permanent or non-permanent mold/die precision cast piston crown, rod flange and piston skirt. The piston crown has a relative constant thickness, a flange requiring minimal machining and a skirt providing for a wall with a support against the angular shifting of the piston. This improves the distribution of heat within such crown and the angular stability of the piston wall at the piston rod connection.

A piston pin assembly is provided including a cylindrical pin body having a hollow interior. A mass is disposed in the hollow interior of the cylindrical pin body and a viscoelastic, plastic, or elastomeric material is disposed in the hollow interior between the mass and the cylindrical pin body. The mass and viscoelastic, plastic, and elastomeric material provides a damper for the piston and piston pin to delay the acceleration of piston lateral motion and stabilize the piston rotation and reduce the noise and friction.

A piston pin assembly is provided including a cylindrical pin body having a hollow interior. A mass is disposed in the hollow interior of the cylindrical pin body and a viscoelastic, plastic, or elastomeric material is disposed in the hollow interior between the mass and the cylindrical pin body. The mass and viscoelastic, plastic, and elastomeric material provides a damper for the piston and piston pin to delay the acceleration of piston lateral motion and stabilize the piston rotation and reduce the noise and friction.

To provide an internal combustion engine that can inject lubricating oil to both of the first region in the skirt of the piston and the second region outside the skirt with fewer nozzles. An internal combustion engine including: a piston configured to reciprocate in a cylinder bore; and an oil injector configured to inject lubricating oil to the piston. The piston includes pin bosses, skirts, side walls, and a piston inner region that is surrounded by respective inner surfaces of the pin bosses, skirts, and side walls. The oil injector is configured to inject the lubricating oil to the pair of pin bosses when the piston is at one of a top dead center and a bottom dead center, and inject the lubricating oil to the piston inner region when the piston is at another of the top dead center and the bottom dead center.

The present invention refers to a piston for an internal combustion engine, particularly a V-engine. The piston comprises an oil drainage groove provided in the outer circumferential surface of the piston between a ring belt and a piston skirt of the piston, the piston skirt being provided with two recessed pin boss portions on opposed sides of the piston, wherein the piston skirt is further provided with at least one oil drainage duct arranged between the two recessed pin boss portions at an outer surface of the piston skirt and configured to fluid-communicatively connect the oil drainage groove with the recessed pin boss portions.

A galleryless piston for an internal combustion engine and method of construction thereof are provided. The piston has a monolithic piston body extending along a central longitudinal axis. The piston body has an upper wall forming an upper combustion surface with first and second portions, with the first portion extending annularly along an outer periphery of the upper wall and the second portion forming a combustion bowl. The upper wall has an undercrown surface on an underside of the combustion bowl directly opposite the second portion of the upper combustion surface. The undercrown surface has an openly exposed surface area, as viewed looking along the central longitudinal axis, thereby providing an expansive area against which oil being splashed or sprayed can freely contact to cool the piston.

A galleryless 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 includes a combustion bowl. The first portion can also include valve pockets formed therein to reduce weight. The upper wall has an undercrown surface directly opposite the second portion of the upper combustion surface. To enhance cooling, a center portion of the undercrown surface is concave, such that oil is channeled during reciprocation of the piston from one side to the opposite side of the piston. The concave center portion is axially offset from the surrounding area of the undercrown surface.

A piston assembly and method of construction thereof for an internal combustion engine are provided. The assembly includes a piston head having an upper combustion wall with an undercrown surface and a ring belt region. The piston head has a floor with an upper surface and a bottom surface. The floor is spaced beneath the upper combustion wall in radial alignment with the ring belt region. A substantially enclosed, annular cooling gallery is bounded by the undercrown surface and the floor. A pair of pin bores depends directly from the floor of the cooling gallery. The assembly further includes a pin having ends configured for oscillating receipt in the pin bores. A pin bearing surface extends within the pin bores and between the pin bores in the lower surface of the floor. The assembly includes a connecting rod with an end fixed to the pin for conjoint oscillation therewith.