Yamaha Hatsudoki Kabushiki Kaisha

Naoki Tsuchida

Hiroyuki Tsuzuku

Takeshi Ito

Tetsushi Saito

Yuji Saiki

Mitsuo Tsuchiya

Hisatoshi Kinoshita

Kazuo Aoi

Masahisa Kuranishi

Hisashi Kazuta

Yasunari Kawai

Yuji Moriwaki

A hydraulic valve driving device includes a valve actuator operable to drive an engine valve, a hydraulic pump that generates the oil pressure for the valve actuator, a hydraulic pump driving motor that drives the hydraulic pump, and a starter motor. At the time of engine starting, after the hydraulic pump is driven by the hydraulic pump driving motor while the crank is stopped in the first engine-starting mode, and then the crank and the hydraulic pump are driven by the starter motor in the second engine-starting mode.

Hydraulic valve driving device and engine including the same and vehicle

An improved cam and follower arrangement suitable for actuating, for example, poppet valves of an internal combustion engine and method and apparatus for forming the cam surface. This permits the use of skewed valve axes without using multiple rocker arms for each valve. The shapes are chosen and formed to provide better contact area and permits the cams to be ground with conventional grinding methods and for multi-cylinder engines.

Three dimensional cam, grinding method and grinding apparatus

A multi-valve internal combustion engine having a plurality of valves having skewed axes that are operated by cam lobes of a single cam shaft. The cam shaft operates the valves through rocker arms each of which are pivoted independently about axes that are skewed relative to the cam shaft axis so as to minimize bending stresses on the valve during its actuation. This also avoids scuffing between the rocker and the valve stem. At the same time, good contact is maintained between the cam lobe and the follower surface by machining the cam lobe so that it will have a slight concavity at least in its tip portion so as to ensure constant line contact with the follower.

Method of forming a camshaft for an engine

Valve operating system for engine

A number of embodiments of induction systems for multiple valve internal combustion engines wherein the performance of the engine is improved throughout the engine speed and load ranges by providing variable effective areas for the induction passages. The embodiments disclosed all relate to three intake valve engines and show a number of different variations in intake passages. In all embodiments an EGR system is employed for improving exhaust emission control.

Induction control system for multi-valve engine

A number of embodiments of twin overhead cam shaft reciprocating machines having a plurality of poppet valves. A variable valve timing mechanism is interposed between the cam shafts and respective of the poppet valves for varying their lift and for changing the number of effective poppet valves per cylinder. The lift changing mechanism includes means for shifting at least one rocker arm follower and provides a relatively compact yet highly efficient structure for achieving this purpose.

Multi valve engine with variable valve operation

A number of embodiments of multi-valve internal combustion engines having a manifold fuel injection and a control valve which changes the air flow pattern into the combustion chamber between an unrestricted flow and a restricted flow wherein turbulence is generated. An air assist arrangement including a number of different embodiments of insert pieces are employed for changing the spray pattern in response to the position of the control valve so as to provide the desired fuel flow into the combustion chamber when the control valve is controlling the air flow.

Air-assisted injection system for multi-valve engine

A cylinder head construction for an internal combustion engine embodying a bonded valve seat so that the flow passages can extend substantially straight through the cylinder head to the valve seat and pass through the center of the valve seat and intersect the center of the respective valve.

Cylinder head and flow passage therefor

Variable valve timing mechanism

Two embodiments of multiple-valve engines wherein both the spark plug and fuel injector are mounted in the cylinder head in side-by-side relationship with their axes lying in a common plane. The spark plug and fuel injector axes extend into the combustion chamber recess in an area that is circumscribed by a circle passing through the centers of the valve seats.

Direction injection system for multi-valve engine

A number of embodiments of multiple-valve internal combustion engines having at least some of the valves being deactivatable by means of a hydraulic tappet assembly so as to control the flow path and flow pattern into and out of the combustion chamber. A hydraulic system is provided for controlling which of the valves operate and, if desired, the lift of the valves.

Valve actuating structure for multi-valve engine

A number of embodiments of valve actuating mechanisms for four-cycle engines including a camshaft and a rocker arm actuated by the camshaft for operating an associated poppet valve. The camshaft and rocker arm followers are configured so as to provide an increasing lever ratio on valve opening for effective rapid valve opening and a decreased lever ratio on valve closing so as to avoid valve bounce. Various arrangements of camshafts and rocker arm positions are disclosed.

Valve operating mechanism for 4-cycle engine

A direct fuel-injected, multivalve, twin overhead cam shaft internal combustion engine. The fuel injector is mounted in the cylinder bore on either the intake or the exhaust side and sprays generally transversely across the diameter of the cylinder bore so as to provide stratification under at least low-speed and low-load conditions. The injector is disposed so that it is positioned below the top of the head of the piston at its top dead center position and a recess is formed in the piston head so as to clear the fuel spray and permit injection even when the piston approaches top dead center without obstruction from the piston. This recess also clears one of the valves.

Growing community of inventors

Iwata, Japan

Naoki Tsuchida