Yamaha Hatsudoki Kabushiki Kaisha

Shigenobu Uchiyama

Masaaki Yoshikawa

Hideo Fujita

Hironao Takahashi

Several embodiments of anti-rotation devices for precluding rotation of the valve actuating lifters or tappet bodies caused by the action of the cam lobe on the engaged surface of the lifter. In each embodiment, the anti-rotation function is achieved without adding to the reciprocating masses of the engine.

Rotation prevention structure of a valve lifter for an internal combustion engine

Several embodiments of variable valve lift mechanisms employing rocker arms that cooperate with high and low speed cam lobes and which are selectively coupled or uncoupled so as to operate the valve dependent upon either the low speed cam lobe configuration or the high speed cam lobe configuration. The construction is such that there are no bending loads placed on the valve stems and the actuating mechanism is relatively light and can be carried at least in part independently of the rocker arms so as to reduce the reciprocating masses and improve engine performance.

High-low speed range switching type valve mechanism for internal combustion engine

A five-valve per cylinder combustion chamber and intake passage arrangement. The side intake passages of the induction system are configured so that the flow exiting them extend toward each other at acute angles and intersect at a point outside of the cylinder bore axis for improving turbulence in the combustion chamber. A fuel injector is also provided which injects fuel only into the side intake passages.

Multi-valve engine

An internal combustion engine having a variable valve timing mechanism with a hydraulic control that is mounted on the front of the cylinder head for ease of accessibility and for ease of conversion of the existing engine. The engine includes an oil filter, oil cooler, and coolant pump, which are disposed and driven in a way so as to maintain short flow paths and permit internal conduits to be formed in the engine so as to avoid the possibility of leakage. The variable valve timing mechanism is controlled by hydraulic pressure supplied by the lubricating system, and a control valve assembly is mounted on the cover for the variable valve timing mechanism with the control passages being formed integrally in this cover. In addition, one of the timing chains may be easily accessed for adjustment without removing the cover through the removal of a bolt that holds an accessory mounting bracket to the engine.

Growing community of inventors

Iwata, Japan

Shigenobu Uchiyama