A piston for an engine is provided, that makes it possible to improve supply of engine oil to a recessed part thereof. The piston includes a resin coating film and a recessed part on a surface of a skirt part. In the piston, resin coating films are distributed in a patchy fashion on the surface of the skirt part. The recessed part is formed by the surface of the skirt part, between adjacent surfaces of the patchy resin coating films and by the adjacent resin coating films, forming a net-like groove. An outer-edge resin coating film, extending in a piston movement direction, is provided at the ends, in a piston circumferential direction of the skirt part.

A piston for an engine is provided, that makes it possible to improve supply of engine oil to a recessed part thereof. The piston includes a resin coating film and a recessed part on a surface of a skirt part. In the piston, resin coating films are distributed in a patchy fashion on the surface of the skirt part. The recessed part is formed by the surface of the skirt part, between adjacent surfaces of the patchy resin coating films and by the adjacent resin coating films, forming a net-like groove. An outer-edge resin coating film, extending in a piston movement direction, is provided at the ends, in a piston circumferential direction of the skirt part.

An iron-based sprayed coating for coating a bore inner surface of a cylinder block for an internal combustion engine. A coating surface contains pits, its pit amount is within a range of 0.01% to 2.1%, and an average roughness Ra of this coating surface is within a range of 0.01 μm to 0.15 μm. The cylinder block for an internal combustion engine includes a bore having this iron-based sprayed coating on its inner surface, and a cylinder block body having the bore. A sliding mechanism for an internal combustion engine includes this cylinder block for an internal combustion engine and a piston slidable with the bore of this cylinder block. The piston has a piston ring, and the piston ring has a chromium coating, a chromium nitride coating, or a diamond-like carbon coating at a sliding part with the bore.

An iron-based sprayed coating for coating a bore inner surface of a cylinder block for an internal combustion engine. A coating surface contains pits, its pit amount is within a range of 0.01% to 2.1%, and an average roughness Ra of this coating surface is within a range of 0.01 μm to 0.15 μm. The cylinder block for an internal combustion engine includes a bore having this iron-based sprayed coating on its inner surface, and a cylinder block body having the bore. A sliding mechanism for an internal combustion engine includes this cylinder block for an internal combustion engine and a piston slidable with the bore of this cylinder block. The piston has a piston ring, and the piston ring has a chromium coating, a chromium nitride coating, or a diamond-like carbon coating at a sliding part with the bore.

A resin coat film 39 formed on a skirt portion 10 of a piston 7 has a four-sided outer peripheral region knurled at upper and lower regions thereof corresponding in a rear view of the piston 7 to an upper skirt part 36 and a lower skirt part 38 of the skirt portion 10 extending in parallel with an axial direction of left and right piston pin boss portions 15 and 14, with a combination of short vertical grooves 43A and 43B and medium-length vertical grooves 42A and 42B extending in parallel with a central axis C of a piston crow portion 9, and at left and right edge regions thereof, with long vertical grooves 41.

A resin coat film 39 formed on a skirt portion 10 of a piston 7 has a four-sided outer peripheral region knurled at upper and lower regions thereof corresponding in a rear view of the piston 7 to an upper skirt part 36 and a lower skirt part 38 of the skirt portion 10 extending in parallel with an axial direction of left and right piston pin boss portions 15 and 14, with a combination of short vertical grooves 43A and 43B and medium-length vertical grooves 42A and 42B extending in parallel with a central axis C of a piston crow portion 9, and at left and right edge regions thereof, with long vertical grooves 41.

An object of the present invention is to, while forming a heat insulating layer on a squish area surface of a top surface of a piston main body, prevent generation of large cracks on the heat insulating layer and suppress damages and peeling of the heat insulating layer. To achieve this object, in the present invention, pressure is applied to a heat insulating layer provided on a top surface of a piston main body, that is, a pressing stress is applied to the heat insulating layer in advance.

Provided are a resin composition for coating an engine piston and a method of fabricating the same. The resin composition contains carbon nanotubes (CNTs) as a reinforcement and is capable of providing a coated layer on at least a part of the engine piston, and the method includes adjusting a parameter expressed as a product of a weight ratio of CNTs in the resin composition and an average aspect ratio of CNTs, to control a coefficient of friction of the coated layer and viscosity of the resin composition.

Provided are a resin composition for coating an engine piston and a method of fabricating the same. The resin composition contains carbon nanotubes (CNTs) as a reinforcement and is capable of providing a coated layer on at least a part of the engine piston, and the method includes adjusting a parameter expressed as a product of a weight ratio of CNTs in the resin composition and an average aspect ratio of CNTs, to control a coefficient of friction of the coated layer and viscosity of the resin composition.

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.