Nippon Piston Ring Co., Ltd.

Hino Jidosha Kabushiki Kaisha

Nippon Piston Ring., Ltd.

Mitsuru Urabe

Hirokazu Murata

Kazuhiko Kanno

Jyuta Tase

Kazumi Moroi

In a sliding structure for an internal combustion, a cylinder has recesses in a stroke center region. Piston rings have inclined surfaces on an outer circumferential surface, and a lubricating oil flows between the inner wall surface and the outer circumferential surface that relatively move via the inclined surfaces. At any RPM equal to or greater than at idle, a center friction coefficient at the stroke center region through which the piston rings pass at the highest speed is less than a center friction coefficient when no recesses are formed in the stroke center region. Contrarily, at the RPM, an outside friction coefficient when the piston rings pass through a region outside the stroke center region is less than an outside friction coefficient when the recesses are formed in the outside region. As a result, further improved low fuel efficiency is achieved for the dimple liner technique.

Sliding structure for internal combustion engine, method for controlling idling operation, and method for controlling operation of internal combustion engine

A cylinder realizing reduced reciprocation friction between a piston ring and a bore surface of the cylinder in a region where the piston ring slides. The cylinder in which a piston slides on a bore surface of the cylinder. A plurality of recesses is formed in a stroke center region in the bore surface of the cylinder. The stroke center region is a region between an under face position of a ring groove for a bottom piston ring at a top dead center of the piston and a top face position of a ring groove for a top piston ring at a bottom dead center of the piston. The total of areas of all of the recesses is in the range of 1% to 80% when an area of the stroke center region is 100%, and the recesses are not formed in a region other than the stroke center region of the bore surface of the cylinder.

Cylinder

Growing community of inventors

Saitama, Japan

Mitsuru Urabe