Ngk Insulators, Inc.

Yasuhiro Miyakawa

Minoru Machida

Seiichi Asami

Akinori Wakasa

A ceramic precombustion chamber construction for an internal combustion engine including a precombustion chamber formed by a ceramic body to be inserted in a precombustion chamber receiving cavity of a metal cylinder head. Projections are formed on an outer circumferential surface of a metal sleeve fitted on the ceramic body, or on an inner circumferential surface of the precombustion chamber receiving cavity of a metal cylinder head, or on an outer circumferential surface of the ceramic body. Thermal insulating spaces are formed by the projections and the inner circumferential surface of the precombustion chamber receiving cavity or the outer circumferential surface of the metal sleeve or the outer circumferential surface of the ceramic body. One of the projections is formed with a glow-plug receiving aperture which communicates with a glow-plug receiving aperture formed in the precombustion chamber receiving cavity of the metal cylinder head. As a result, leakage of burnt gases is prevented to ensure a complete thermal insulating effect.

Precombustion chamber construction for an internal combustion engine

A cylinder head has a ceramic precombustion chamber for an internal combustion engine. The cylinder head includes a part of the cylinder head made of a ceramic body having an injection aperture communicating with a main combustion chamber for jetting burning gases therethrough, a metal sleeve fitted on an outer circumference of the ceramic body and fitted in a precombustion chamber insert bore forming part of the cylinder head, and a head gasket interposed between the cylinder block forming the main combustion chamber and the ceramic body, the metal sleeve and the cylinder head. A surface of the ceramic body facing to the head gasket extends onto a side of the main combustion chamber beyond a surface of the ceramic body opening the injection aperture into the main combustion chamber.

Cylinder head with ceramic precombustion chamber

A precombustion chamber construction for an internal combustion engine comprises a precombustion chamber constructed by a ceramic body having a glow-plug receiving aperture to be inserted in a precombustion chamber receiving cavity of a metal cylinder head. A metal sleeve may be fitted on the ceramic body. A seat is formed at an entrance of a glow-plug receiving aperture on an outer circumferential surface of the metal sleeve, thereby preventing any leakage of burnt gases to ensure the complete thermal insulating effect. The metal sleeve is not necessarily needed. In this case, the seat is formed at an entrance of the glow-plug receiving aperture on an outer circumferential surface of the ceramic body.

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Nagoya, Japan

Yasuhiro Miyakawa