Yutaka Giken Co., Ltd.

Honda Giken Kogyo Kabushiki Kaisha

Honda Motor Co., Ltd.

Isao Hirokawa

Masayuki Uegane

Yasuyuki Watanabe

Hideyuki Ushiyama

Atsumu Naoi

Tetsuaki Nakayama

Toshihiro Kondo

Katsunori Muramatsu

Kazuhiro Tsuda

Hidenori Ozawa

Ryoichi Matsushima

A heat exchange tube is constructed by forming, on a cylindrical tube peripheral wall, a plurality of projecting portions which project to an inside of the tube peripheral wall, and which are formed by pushing. The plurality of projecting portions are formed, respectively, into conical shapes across a tube axis, and are arranged along virtual spirals on the tube peripheral wall. Accordingly, it is possible to provide a heat exchange tube which facilitates formation of a plurality of projecting portions with the thickness hardly changed and without formation of protruded portions, and which is capable of contributing to enhancement of heat exchanging efficiency.

Heat exchange tube

A valve device for a silence opens a bypass passage provided in the silencer to flow exhaust gas through the bypass passage when exhaust gas pressure rises to a certain pressure. The valve device includes a base having a valve opening through which exhaust gas flows, and a plate-like valve for opening and closing the valve opening. The plate-like valve is fixed to the base at its proximal portion, and is bent at both edges thereof in a certain range extending from its distal end toward the proximal portion.

Valve device for silencer

An exhaust system in an internal combustion engine includes a flow rate regulating valve which is positioned in an intermediate portion of an exhaust gas flow passage. The flow rate regulating valve has a rotary shaft rotatably supported in a valve housing, and a rotationally biasing spring mounted between the rotary shaft and the valve housing which provides a spring force to rotationally bias the rotary shaft. In the exhaust system, an axially biasing spring is mounted separately from the rotationally biasing spring between the valve housing and the rotary shaft for biasing the rotary shaft in an axial direction. The rotary shaft is provided with an abutment surface which faces in the one axial direction, and the valve housing is provided with a limiting portion which abuts against the abutment surface to limit the axial movement of the rotary shaft. Thus, the rotary shaft is biased in the one axial direction by the axially biasing spring, and the abutment surface of the rotary shaft is urged against the limiting portion of the valve housing, thereby avoiding the axially chattering of the rotary shaft.

Exhaust system in internal combustion engine

Growing community of inventors

Hamamatsu, Japan

Isao Hirokawa