Honda Giken Kogyo Kabushiki Kaisha

Honda Motor Co., Ltd.

Junichi Ishida

Hiroyuki Uchida

Takanori Osuka

Masaaki Negoro

Tomiyuki Sasaki

Shigeyuki Hara

Yosuke Ariga

Kazuaki Namiki

A motorcycle includes an engine configured to expel an exhaust from combustion chambers of cylinders in a cylinder head through exhaust ports. Each of the cylinders is provided with a recessed portion provided in an exhaust passage wall surface in a central portion of an exhaust passage of a corresponding exhaust port. This makes it possible to maintain flow rate and flow velocity of the exhaust gas, and to decrease exhaust loss. As a result, it is possible to increase engine torque by use of a simple structure. In addition, no restriction is imposed on the layout of parts around the engine, because the recessed portions are provided in the exhaust ports.

Cylinder head for an internal combustion engine, engine incorporating the cylinder head, and method of making same

An internal combustion engine for enhancing a heat radiation property of combustion gas, can sufficiently secure strength thereof relative to combustion gas, and a weight reduction thereof can be realized. A piston for an internal combustion engine is constituted of a head part, a cylindrical skirt part extending from a lower part of the head part. A pair of pin boss parts are formed on both opposing side walls to each other of the skirt part. A plurality of recessed parts, the cross sections thereof being presented as smooth circular arcs, are formed on a surface on an opposing side to a surface facing to a combustion chamber of the head part, that is, to a reverse face.

Piston for internal combustion engine

A common drive shaft for first and second exhaust control valves is formed of a single piece. A first exhaust valve adjusting exhaust timing and a second exhaust valve adjusting a sectional area of an exhaust passage are provided on the common drive shaft. The second exhaust valve is rotated integrally with the drive shaft. The first exhaust valve is fitted on the drive shaft via an intermediate sleeve and a torsion coil spring. A linkage mechanism is provided so that the intermediate sleeve is stopped at a limit of rotation of the first exhaust valve. Thereafter, only the second exhaust valve is rotated.

Exhaust valve device for two-cycle engine

Growing community of inventors

Saitama, Japan

Junichi Ishida