Aisin Seiki Kabushiki Kaisha

Toyota Jidosha Kabushiki Kaisha

Aisin Seiki Kabushiki

Hiroshi Kageyama

Soichi Hara

Yasuhiro Kawabata

Shirou Machida

Motoichi Murakami

Toshiaki Konomi

Hara Soichi

Disclosed is a piston for an internal combustion engine, which includes a land portion, and a skirt portion including a non-coated portion which is formed in an arbitrary shape on a sliding portion thereof and a coated portion which is formed on a sliding portion thereof other than the sliding portion on which the non-coated portion is formed. When the piston is descending, an oil which has adhered on a cylinder bore is introduced into the non-coated portion and accordingly an oil film is established in the non-coated portion. Since the advantageous effects of the coated portion and the oil film are combined in the piston, the sliding resistance can be reduced remarkably. Hence, the coated portion can be inhibited from wearing out, and its function of the sliding resistance reduction can be maintained for a long period of time. In addition, since the non-coated portion does not work as a sliding surface, there arises a reduced sliding surface area which also results in the reduction of the sliding resistance. The non-coated portion and the coated portion can be formed with a resin by printing. If such is the case, they can be formed with ease and at a less production cost.

Piston for an internal combustion engine

A piston comprises a crown part, a piston under part, a first shoulder at a thrust side formed between the crown part and the piston under part, a second shoulder at an anti-thrust side formed between the crown part and the piston under part, a first in-low part at the thrust side formed in the piston under part, and a second in-low part at the anti-thrust side formed in the piston under part, wherein a thickness of the first shoulder is formed thinner than a thickness of the second shoulder, and a height of the first in-low part is formed smaller than a height of the second in-low part.

Piston for internal combustion engine

A piston installed into a cylinder of an engine includes annular projections formed in axially spaced relation on a top land facing a cylinder inner wall and having a saw-toothed cross-section in which the external diameter of the projections are such that, when cold, that adjacent the lower end of the top land is greater than that adjacent the upper end thereof. Thereby the effective clearance between the top land face and the cylinder inner wall is reduced. This causes a reduction in the hydrocarbon content of the incompletely consumed combustion gas, and prevents the temperature from rising in the top ring groove and thus prevents the wearing of the groove.

Internal combustion engine piston with top-land circumferential

A piston is formed with a cooling channel in its crown by dissolving a fusible core cast into the crown. The fusible core is supported prior to casting by a strut which is itself supported on a plurality of cores which help to find the piston cavity. The plurality of cores are configured so as to be removable from the strut, after casting, in a downward direction. The fusible core is dissolved by introducing a dissolving liquid to the fusible core via inlet or outlet passages cut between the cavity and the fusible core.

Piston assembly having a fusible core to form a cooling channel and a

A method of manufacturing a piston of an internal combustion engine includes holding a soluble core to a plurality of first projection portions and a plurality of second projection portions and a plurality of third projection portions formed in a pair of straight portions of a strut member for preventing thermal expansion of the piston. The first projections have a bent portion bent outwardly so as to be along an inner face of the soluble core and the second projection portions have a curved holding portion bent inwardly so as to be along a lower surface and inner surface of the soluble core. By holding the strut member and the soluble core in the piston, the soluble core is melted away and an oil-cooling gallery is formed by pouring water into the mold.

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Toyota, Japan

Hiroshi Kageyama