Yamaha Hatsudoki Kabushiki Kaisha

Tateo Aoyama

Masahiro Uchida

Kenichi Sakurai

Masato Nishigaki

Takashi Hara

Masami Wada

Shigeo Yamamoto

A number of embodiments of cylinder head and intake port arrangements for multiple valve, internal combustion engines particularly those having three or more intake valves. The configuration promotes turbulence in the combustion chamber by inducing a tumble action even from the center intake valve seat. In addition, each of the valve seats and its associated flow passages are configured so as to provide optimum tuning for different engine speeds so as to improve the torque of the engine throughout its entire speed and load ranges and to provide good breathing efficiency throughout all engine speeds. Various porting and throttle and fuel injection systems are shown wherein siamesed intake passages are formed for at least two of the valve seats.

Induction system for engine

A control valve arrangement for a three-valve-per-cylinder internal combustion engine. The control valve arrangement controls not only the effective length of the intake passage serving each combustion chamber, but also controls the flow through the intake passage so as to generate turbulence under low-speed and low-load conditions. The control valve further includes a pair of valves which change not only the effective flow area, but also the effective flow direction. In this way varying degrees and types of turbulence can be generated during different engine running conditions. A number of different types of valve arrangements are disclosed.

Intake control system for generating tumble action

A five valve per cylinder twin overhead cam internal combustion engine wherein the valve placement is such that the cam shafts may be located so as to directly operate the valves and still provide threaded fastener attachments that can be tightened when the cam shaft is in place. The placement of the valves and the size of their actuating tappets is such to maintain optimum strength and durability while maintaining a compact construction.

Cylinder head for tappet arrangement for multi-valve engine

Cylinder head for multi-valve engine

A number of embodiments of three valve per cylinder engines which permit effective running under all engine running conditions by controlling the flow to some of the intake ports and by redirecting the flow, in some instances to other intake ports. A wide variety of control valves and fuel injector arrangements are also disclosed.

Cylinder head porting arrangement for multi-valve engine

A V-type multi-valve twin overhead cam shaft internal combustion engine and induction system therefor. The cylinder heads of the engine are formed as a unitary assembly for supporting the valves, the tappets that actuate the valves and the overhead cam shafts.

Cylinder head arrangement for multi-valve engine

Several embodiments of variable camshaft timing means for twin overhead cam engines. There is provided a first timing altering means between the engine output shaft and one of the camshafts and a second timing altering means that is operative between the one camshaft and the other camshaft. Both timing altering means are operated by the same hydraulic pressure in several embodiments and a locking device is incorporated so as to avoid self-induced timing adjustment due to the change in driving loads.

Growing community of inventors

Iwata, Japan

Tateo Aoyama