The present disclosure provides a piston, comprising: a skirt having an upper body portion; and a crown formed on the upper body portion by an additive manufacturing process, the crown including at least one air gap formed and positioned to reduce heat transfer from combustion to at least one cooling gallery formed in the piston.

The present disclosure provides a piston, comprising: a skirt having an upper body portion; and a crown formed on the upper body portion by an additive manufacturing process, the crown including at least one air gap formed and positioned to reduce heat transfer from combustion to at least one cooling gallery formed in the piston.

A piston for an internal combustion engine is provided. The piston includes a coating applied to a ferrous body portion to reduce or prevent chemical bonding of carbon deposits or coking on the body portion at temperatures ranging from 200 to 400° C. The coating includes a fluoropolymer, such as polytetrafluoroethylene, fluorosilane, fluorocarbon, fluoroplastic resin, and/or perfluoroplastic, and may be hydrocarbon or silicone based. The coating also has a thickness of 25 microns to 1 millimeter. The coating can be disposed on an undercrown surface, ring grooves, ring lands, pin bosses, and/or skirt sections of the body portion.

A piston for an internal combustion engine is provided. The piston includes a coating applied to a ferrous body portion to reduce or prevent chemical bonding of carbon deposits or coking on the body portion at temperatures ranging from 200 to 400° C. The coating includes a fluoropolymer, such as polytetrafluoroethylene, fluorosilane, fluorocarbon, fluoroplastic resin, and/or perfluoroplastic, and may be hydrocarbon or silicone based. The coating also has a thickness of 25 microns to 1 millimeter. The coating can be disposed on an undercrown surface, ring grooves, ring lands, pin bosses, and/or skirt sections of the body portion.

The present disclosure provides a piston, comprising: a skirt having an upper body portion; and a crown formed on the upper body portion by an additive manufacturing process, the crown including at least one air gap formed and positioned to reduce heat transfer from combustion to at least one cooling gallery formed in the piston.

The present disclosure provides a piston, comprising: a skirt having an upper body portion; and a crown formed on the upper body portion by an additive manufacturing process, the crown including at least one air gap formed and positioned to reduce heat transfer from combustion to at least one cooling gallery formed in the piston.

In an internal combustion engine provided with a combustion chamber defined by an inner circumferential surface of a cylinder, an end surface of a cylinder head facing the cylinder, a crown surface of a piston, an inner surface of an intake valve, and an inner surface of an exhaust valve, for the purpose of improving the anti-knocking performance of the engine, the inner circumferential surface of the cylinder, the end surface of the cylinder head, the crown surface of the piston, the inner surface of the intake valve and the inner surface of the exhaust valve include a mirror surface region formed as a mirror surface having an arithmetic average roughness of 0.3 μm or less, and a rough surface region formed as a rough surface having an arithmetic average roughness of 0.3 μm or more.

In an internal combustion engine provided with a combustion chamber defined by an inner circumferential surface of a cylinder, an end surface of a cylinder head facing the cylinder, a crown surface of a piston, an inner surface of an intake valve, and an inner surface of an exhaust valve, for the purpose of improving the anti-knocking performance of the engine, the inner circumferential surface of the cylinder, the end surface of the cylinder head, the crown surface of the piston, the inner surface of the intake valve and the inner surface of the exhaust valve include a mirror surface region formed as a mirror surface having an arithmetic average roughness of 0.3 μm or less, and a rough surface region formed as a rough surface having an arithmetic average roughness of 0.3 μm or more.

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 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.