Honda Giken Kogyo Kabushiki Kaisha

Masahiko Matsumoto

Koichi Fukuo

Toshiaki Hiro

Mitsuhiro Shibata

Kazuhide Kumagai

A hydraulic circuit for a valve operation timing control device for an internal combustion engine which has a low-speed cam having a shape suited for low-speed operation of the engine, a high-speed cam having a shape suited for high-speed operation of the engine, the low- and high-speed cams being integrally formed on a camshaft rotatable in synchronism with a crankshaft, a first rocker arm held in slidable contact with the low-speed cam, a second rocker arm held in slidable contact with the high-speed cam. The first and second rocker arms are adjacent to and in slidable contact with each other and pivotably supported on a rocker shaft for relative angular displacement. There is a first oil feed passage for lubricating the low-speed cam and a second oil feed passage for lubricating the high-speed cam. The first rocker arm has a hydraulic lash adjuster and a relief valve is disposed in the oil passage for supplying oil pressure to said hydraulic lash adjuster for maintaining a predetermined oil pressure on the hydraulic lash adjuster.

Hydraulic circuit for a valve operating timing control device for an

A valve operating mechanism for an internal combustion engine has a low-speed cam for operating the intake or exhaust valves during low-speed operation of the engine and a high-speed cam for operating the intake or exhaust valves during high-speed operation of the engine. A low-speed lubricating oil passage is provided for supplying lubricating oil to the low-speed cam and a separate high-speed lubricating oil passage is provided for supplying lubricating oil to the high-speed cam. A control valve is connected to said low-speed and high-speed lubricating oil passages for selectively supplying maximum oil pressure to the high-speed lubricating oil passage during high-speed operation while restricting the rate of flow of oil during low-speed operation of the engine and supplying maximum oil pressure to the low-speed lubricating oil passage during low-speed operation of the engine while restricting or eliminating the oil supplied thereto during high-speed operation.

Growing community of inventors

Saitama, Japan

Masahiko Matsumoto