Toyota Jidosha Kabushiki Kaisha

Teikoku Piston Ring Co., Ltd.

Teipi Industry Co., Ltd.

Toshihiro Mihara

Satoshi Yamada

Nobuyuki Yamashita

Noritaka Miyamoto

Toshihiro Takami

Takashi Sato

Masaki Hirano

Giichiro Saito

Masami Horigome

Kouhei Shibata

Takeshi Tsukahara

Yukinori Ohta

Kouhei Hori

A cylinder liner has an upper portion and a lower portion with respect to an axial direction of the cylinder liner. A high thermal conductive film is provided on an outer circumferential surface of the upper portion. A low thermal conductive film is provided on an outer circumferential surface of the lower portion. The cylinder liner reduces temperature difference of a cylinder along its axial direction.

Cylinder liner and engine

A cylinder lineris enveloped in a cylinder block through insert casting. The cylinder linerincludes a cylinder liner bodyand a metal coating layerformed on the bodythrough a cold spraying method. Since the metal coating layeris formed in a non-molten and oxygen free state, few oxygen films or oxygen layers are formed on the surface of or in the interior of the metal coating layer. Thus, the thermal conductivity of the metal coating layeris sufficiently high. As a result, the thermal conductivity from the metal coating layerto the cylinder block is sufficiently high.

Component for insert casting, cylinder block, and method for manufacturing cylinder liner

A cylinder liner has an outer circumferential surface on which a film is formed. The film functions to form gaps between the cylinder block and the cylinder liner. Alternatively, the film functions to reduce adhesion of the cylinder liner to the cylinder block. The cylinder liner suppresses excessive decreases in the temperature of a cylinder.

Cylinder liner and method for manufacturing the same

A cylinder liner for insert casting used in a cylinder block is disclosed. The cylinder liner has an outer circumferential surface, and upper, middle, and lower portions with respect to an axial direction of the cylinder liner. A high thermal conductive film is formed in a section of the outer circumferential surface that corresponds to the upper portion, and a low thermal conductive film is formed in a section of the outer circumferential surface that corresponds to the lower portion. The high thermal conductive film and the low thermal conductive film are laminated in a section of the outer circumferential surface that corresponds to the middle portion, thereby forming a laminated film portion. As a result, temperature difference along the axial direction of the cylinder is reduced.

A cylinder liner for an engine cylinder block. A roughening process is performed only on an upper region of the outer surface of the cylinder liner. This increases adhesiveness with a sprayed layer at the upper region compared to a lower region of the liner outer surface. Therefore, difference in thermal conductance is produced in the axial direction of the cylinder liner. This maintains the wall temperature of the cylinder bore in an appropriate temperature range. Even if adhesiveness at the lower region of the liner outer surface is low, bottleneck-shaped projections are distributed on the liner outer surface. Thus, the bonding strength between the cylinder liner and the sprayed layer and the cylinder liner and the cylinder block via the sprayed layer is sufficient. This maintains the roundness of the cylinder bore and prevents fuel efficiency from being lowered by exhaust gas loss and mechanical loss.

Cylinder liner, cylinder block, and method for manufacturing cylinder liner

A liner outer surface is coated by a sprayed layer or a heterogeneous metal layer including a base metal phase and dispersed metal phases. During casting, liquid metal enters the sprayed layer from the dispersed metal phases and solidifies in a virtual vegetation root state. The surface of the cylinder block is thus rigidly fixed to the surface of the cylinder liner. In this case, a strong bonding force is produced between the cylinder block and the cylinder liner and high thermal conductivity is obtained compared to the prior art in which the liquid metal merely contacts a surface layer.

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Matsumoto, Japan

Toshihiro Mihara