An improved piston forging for use in an internal combustion engine is disclosed. The piston forging comprises a crown, a pair of pin towers extending generally axially away from the crown, and a skirt extending generally axially away from the crown. The improved piston forging further comprises a plurality of grains flowing across the piston forging. The plurality of grains are reoriented during the forging operation into a configuration that follows the surfaces and features of the piston forging. More specifically, the plurality of grains are reoriented in a manner that is most beneficial to resist combustion and inertial forces that are enacted upon a machined piston during operation.

A piston of an internal-combustion engine may include a piston head and a piston skirt, a cooling duct circulating in the piston head, a boss for receiving a piston pin, and a feed hopper for supplying cooling oil into the cooling duct. The feed hopper may be fastened to another component of the piston via a retaining lug by at least one of a material closure, a force closure, and a positive closure.

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 for an internal combustion engine comprises a skirt defining an inner space of the piston and having a skirt bottom; and a target arranged under the skirt bottom to engage with a passage detector arranged in the engine. The target is supported by a holding body held at least partially inside the inner space of the piston. The present disclosure likewise relates to an engine comprising such a piston.

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 surface, and a portion of either an open outer cooling gallery, a sealed outer cooling gallery, or an outer galleryless region, wherein an insulating coating is applied to at least one of the portions of 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 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.

A steel piston for coupling to a connecting rod and wrist pin is provided. The piston includes a body with an upper crown presenting a combustion surface for exposure to a combustion chamber. The upper crown presents an undercrown surface which is openly exposed as viewed from an underside of the piston and not bounded by a cooling gallery. The body includes a ring belt and pin bosses depending from the ring belt and presenting a pin bore for receiving the wrist pin. The body also includes ribs disposed along the undercrown surface. The body includes a ratio of compression height to outer diameter (CH/D) ranging from 34.8% to 42.0%. The piston also includes a low heat transfer coating on the combustion surface, and the low heat transfer coating has a thermal conductivity of about 0.20 to 0.80 W/m.Math.K.

A piston of an internal-combustion engine may include a piston head and a piston skirt, a cooling duct circulating in the piston head, a boss for receiving a piston pin, and a feed hopper for supplying cooling oil into the cooling duct. The feed hopper may be fastened to another component of the piston via a retaining lug by at least one of a material closure, a force closure, and a positive closure.

An improved piston forging for use in an internal combustion engine is disclosed. The piston forging comprises a crown, a pair of pin towers extending generally axially away from the crown, and a skirt extending generally axially away from the crown. The improved piston forging further comprises a plurality of grains flowing across the piston forging. The plurality of grains are reoriented during the forging operation into a configuration that follows the surfaces and features of the piston forging. More specifically, the plurality of grains are reoriented in a manner that is most beneficial to resist combustion and inertial forces that are enacted upon a machined piston during operation.