Honda Motor Co., Ltd.

Yoshihiro Okada

Masanobu Takazawa

Naoaki Takeda

Kouichi Ikoma

Akinori Maezuru

Masakazu Kinoshita

Koichi Eto

Naokazu Kawase

Shinya Abe

Koichi Ikoma

Kazuhiko Iso

Hidehumi Kuramitsu

Katsuya Minami

An internal combustion engine includes an engine main body defining a cylinder bore, a piston received in the cylinder bore, and a crankshaft rotatably supported by the engine main body and connected with the piston via a connecting rod, the piston including a skirt. The cylinder bore includes a first region defined as a range along the cylinder axial line on a side of a top dead center from a first piston position, and a second region defined as a range along the cylinder axial line on a side of the bottom dead center from a second piston position closer to the bottom dead center than the first piston position, and a connection region positioned between the first and second regions. A diameter of the cylinder bore is smaller in the first region than in the second region, and the connection region connects the first and second regions smoothly.

Internal combustion engine

Secondary vibration generated accompanying reciprocation of a piston () of a multi-link variable compression ratio engine (E) can be eliminated effectively, even when the direction of the secondary vibration is inclined relative to a cylinder axis (L), by inclining the direction (shown by arrow) of an excitation force generated by a secondary balancer system () so that it coincides with the direction of the secondary vibration. The secondary balancer system () is formed by supporting balancer weights () on a pair of balancer shafts () rotating in directions opposite to each other, and by displacing the phases of these balancer weights () the direction of the excitation force generated can be inclined so as to coincide with the direction of secondary vibration of the engine (E).

Engine vibration elimination system and variable stroke characteristic engine

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Wako, Japan

Yoshihiro Okada